Publications
BGC is dedicated to furthering the study of the innovations in the industries we serve. As part of our team’s professional development, BGC experts co-author articles and technical publications and present many of them at industry conferences. Recent publications by BGC staff are listed below. To request a copy of a publication, please reach out to our BGC Library team at library@bgcengineering.ca. Due to copyright issues, we may not be able to provide copies of all the publications listed below.
2023
Walton, Gabriel; Weidner, Luke
Accuracy of Rockfall Volume Reconstruction from Point Cloud Data—Evaluating the Influences of Data Quality and Filtering Journal Article
In: Remote Sensing, vol. 15, no. 1, 2023.
@article{journal1,
title = {Accuracy of Rockfall Volume Reconstruction from Point Cloud Data—Evaluating the Influences of Data Quality and Filtering},
author = {Gabriel Walton and Luke Weidner},
doi = {10.3390/rs15010165},
year = {2023},
date = {2023-12-31},
urldate = {2023-12-30},
journal = {Remote Sensing},
volume = {15},
number = {1},
abstract = {Rockfall processes are now commonly studied through monitoring campaigns using repeat lidar scanning. Accordingly, several recent studies have evaluated how the temporal resolution of data collection and various data-processing decisions can influence the apparent rockfall volumes estimated using typical rockfall database creation workflows. However, there is a lack of studies that consider how data quality and associated data-processing decisions influence rockfall volume estimation. In this work, we perform a series of tests based on an existing reference rockfall database from the Front Range of Colorado, USA, to isolate the influences of data resolution (point spacing), individual point precision, and the filter threshold applied to change results, on the volume estimates obtained for rockfalls. While the effects of individual point precision were found to be limited for typical levels of gaussian noise (standard deviation per coordinate direction ≤ 0.02 m), data resolution and change filter threshold were found to have systematic impacts on volume estimates, with the volume estimates for the smallest rockfalls decreasing substantially with increases in point spacing and change filter threshold. Because these factors disproportionately impact volume estimates for smaller rockfalls, when these factors change, the slope of the apparent power law that describes the relative frequency-volume distribution of rockfalls changes. Evidence is presented that suggests that this phenomenon can explain discrepancies between power law slopes presented in the literature based on studies focused on different scales of rockfall activity. Overall, this study demonstrates the impacts of raw data attributes on rockfall volume estimation and presents an additional effect that tends to bias rockfall frequency–magnitude power law relationships towards underestimation of the relative prevalence of small rockfalls.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Rockfall processes are now commonly studied through monitoring campaigns using repeat lidar scanning. Accordingly, several recent studies have evaluated how the temporal resolution of data collection and various data-processing decisions can influence the apparent rockfall volumes estimated using typical rockfall database creation workflows. However, there is a lack of studies that consider how data quality and associated data-processing decisions influence rockfall volume estimation. In this work, we perform a series of tests based on an existing reference rockfall database from the Front Range of Colorado, USA, to isolate the influences of data resolution (point spacing), individual point precision, and the filter threshold applied to change results, on the volume estimates obtained for rockfalls. While the effects of individual point precision were found to be limited for typical levels of gaussian noise (standard deviation per coordinate direction ≤ 0.02 m), data resolution and change filter threshold were found to have systematic impacts on volume estimates, with the volume estimates for the smallest rockfalls decreasing substantially with increases in point spacing and change filter threshold. Because these factors disproportionately impact volume estimates for smaller rockfalls, when these factors change, the slope of the apparent power law that describes the relative frequency-volume distribution of rockfalls changes. Evidence is presented that suggests that this phenomenon can explain discrepancies between power law slopes presented in the literature based on studies focused on different scales of rockfall activity. Overall, this study demonstrates the impacts of raw data attributes on rockfall volume estimation and presents an additional effect that tends to bias rockfall frequency–magnitude power law relationships towards underestimation of the relative prevalence of small rockfalls.
McClymont, Alastair; Johnson, Eric; Wenger, Greg; Bates, Caroline; Ruksys, Annabel; Wang, Rita; Dickinson, Simon; Regli, Andrea
An Optimized Geotechnical and Geophysical Site Investigation for Derisking Future Mine Tailings Storage at DLM, Canada Conference
EEGS / AEG 2023 Virtual Symposium, 2023.
@conference{Conference1,
title = {An Optimized Geotechnical and Geophysical Site Investigation for Derisking Future Mine Tailings Storage at DLM, Canada},
author = {Alastair McClymont and Eric Johnson and Greg Wenger and Caroline Bates and Annabel Ruksys and Rita Wang and Simon Dickinson and Andrea Regli},
year = {2023},
date = {2023-12-29},
urldate = {2023-12-30},
booktitle = {EEGS / AEG 2023 Virtual Symposium},
abstract = {The Detour Lake Mine (DLM) in northern Ontario is one of the largest gold producing mines in Canada. With an expected mine life of at least 22 years, future tailings storage is required to accommodate expansion plans. The local geology comprises low, flat-lying, poorly exposed bedrock ridges, predominantly covered by glacial sediments and organic soil of variable thickness. Because variation in the thickness of the cover materials impacts the design of proposed future ring-dikes, mapping the variability in the foundation materials is essential to accurately estimate construction costs and ensure that the dikes are built for the safe containment of tailings well beyond the expected life of the mine. Since these subsurface conditions can change markedly over relatively short distances, conventional drilling and test pit programs that sample at discrete locations run the risk of missing anomalous geological features, including deep bedrock channels and faults that may underly the footprint of the ring dikes. Conversely, drilling or test pitting over dense intervals to capture this variability can significantly increase costs for a site investigation. We present the results of a site investigation that utilized multiple geophysical methods to efficiently map and characterize the subsurface and optimize a follow-up test pitting program. A specialized ground-penetrating radar (GPR) system, together with electrical resistivity tomography (ERT) and targeted seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW) profiles were obtained along the proposed footprint of the ring-dike system. The GPR results mapped organic soil thickness variations of up to 4 m, and the ERT and SRT profiles revealed two distinct bedrock troughs intersecting the dike footprint, one as deep as 38 m. 47 test pits were then completed at targeted locations, informed by the geophysical results and to help ground-truth the geophysical interpretations and characterize geotechnical conditions within the foundation soils.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The Detour Lake Mine (DLM) in northern Ontario is one of the largest gold producing mines in Canada. With an expected mine life of at least 22 years, future tailings storage is required to accommodate expansion plans. The local geology comprises low, flat-lying, poorly exposed bedrock ridges, predominantly covered by glacial sediments and organic soil of variable thickness. Because variation in the thickness of the cover materials impacts the design of proposed future ring-dikes, mapping the variability in the foundation materials is essential to accurately estimate construction costs and ensure that the dikes are built for the safe containment of tailings well beyond the expected life of the mine. Since these subsurface conditions can change markedly over relatively short distances, conventional drilling and test pit programs that sample at discrete locations run the risk of missing anomalous geological features, including deep bedrock channels and faults that may underly the footprint of the ring dikes. Conversely, drilling or test pitting over dense intervals to capture this variability can significantly increase costs for a site investigation. We present the results of a site investigation that utilized multiple geophysical methods to efficiently map and characterize the subsurface and optimize a follow-up test pitting program. A specialized ground-penetrating radar (GPR) system, together with electrical resistivity tomography (ERT) and targeted seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW) profiles were obtained along the proposed footprint of the ring-dike system. The GPR results mapped organic soil thickness variations of up to 4 m, and the ERT and SRT profiles revealed two distinct bedrock troughs intersecting the dike footprint, one as deep as 38 m. 47 test pits were then completed at targeted locations, informed by the geophysical results and to help ground-truth the geophysical interpretations and characterize geotechnical conditions within the foundation soils.
Wlodarczyk, Kyle; Hassan, Marwan; Church, Michael
Annual and Decadal Net Morphological Displacement of a Small Gravel-Bed Channel Journal Article
In: Earth Surface Processes and Landforms, vol. 48, no. 8, pp. 1630-1645, 2023.
@article{journal1,
title = {Annual and Decadal Net Morphological Displacement of a Small Gravel-Bed Channel},
author = {Kyle Wlodarczyk and Marwan Hassan and Michael Church},
doi = {10.1002/esp.5572},
year = {2023},
date = {2023-12-28},
urldate = {2023-12-30},
journal = {Earth Surface Processes and Landforms},
volume = {48},
number = {8},
pages = {1630-1645},
abstract = {The sediment supplied to a stream channel impacts the morphological trends experienced by that channel, and the long-term trends are important to understand for many riverine applications. We introduce the term ‘net morphological displacement’ (NMD) to denote the net channel change revealed by the morphological method over multiple sediment transport events to make the concept more explicit for river management and use it to determine equilibrium or disequilibrium states. This study explores the morphological response of East Creek, a small threshold gravel-bed channel in the Coast Mountains of British Columbia, Canada, to variations in flow and sediment supply at multiple spatial and temporal scales over 15 years. High-resolution topographic data (HRTD) of the bed were combined with cross-sectional surveys of the banks to determine the sediment supply that the channel responded to annually. The level of detection used to remove noise associated with HRTD was calibrated using an independent tracer stone dataset. The net effects from multiple floods caused distributions of bed elevation change to generally follow the log-normal distribution, and mean depths of erosion and deposition were predominantly similar between morphological units. At the reach scale, the various reaches of East Creek responded differently to the same hydrological events due to the impacts from the varying supply conditions on the NMD. Shorter measurement periods would have resulted in inconclusive information that does not show the long-term morphological trends of the channel. Determination of these trends can take years or decades, depending on the time and space scales of change, but there is generally a lack of long-term channel monitoring programmes, notably after river restoration. More long-term channel monitoring programmes are required to assess restoration projects and ensure their long-term sustainability.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The sediment supplied to a stream channel impacts the morphological trends experienced by that channel, and the long-term trends are important to understand for many riverine applications. We introduce the term ‘net morphological displacement’ (NMD) to denote the net channel change revealed by the morphological method over multiple sediment transport events to make the concept more explicit for river management and use it to determine equilibrium or disequilibrium states. This study explores the morphological response of East Creek, a small threshold gravel-bed channel in the Coast Mountains of British Columbia, Canada, to variations in flow and sediment supply at multiple spatial and temporal scales over 15 years. High-resolution topographic data (HRTD) of the bed were combined with cross-sectional surveys of the banks to determine the sediment supply that the channel responded to annually. The level of detection used to remove noise associated with HRTD was calibrated using an independent tracer stone dataset. The net effects from multiple floods caused distributions of bed elevation change to generally follow the log-normal distribution, and mean depths of erosion and deposition were predominantly similar between morphological units. At the reach scale, the various reaches of East Creek responded differently to the same hydrological events due to the impacts from the varying supply conditions on the NMD. Shorter measurement periods would have resulted in inconclusive information that does not show the long-term morphological trends of the channel. Determination of these trends can take years or decades, depending on the time and space scales of change, but there is generally a lack of long-term channel monitoring programmes, notably after river restoration. More long-term channel monitoring programmes are required to assess restoration projects and ensure their long-term sustainability.
Kimball, Julia; Bowman, Elisabeth; Gray, Nico; Take, Andy
EGU General Assembly, 2023.
@conference{Conference1,
title = {Assessing Experimental Methods for the Quantification of Particle Size Segregation in Large Scale Flume Tests using Image Analysis},
author = {Julia Kimball and Elisabeth Bowman and Nico Gray and Andy Take},
doi = {10.5194/egusphere-egu23-10517},
year = {2023},
date = {2023-12-27},
urldate = {2023-12-30},
booktitle = {EGU General Assembly},
abstract = {Particle size segregation is a phenomenon that generates preferential sorting of particles, based on size, in material flows of non-uniform size distribution. Landslide hazards, such as debris flows, involve materials of non-uniform particle sizes and therefore generate flow structures which arise from particle size segregation. The mobility, distal reach and impact forces associated with these natural hazards are influenced by these processes. Understanding the mechanisms of this phenomenon is essential for acquiring accurate input parameters that are needed to model these flows and properly design debris flow barriers and retaining structures. While the dynamics of particle size segregation in flow and deposition have been furthered through studying granular flows, studies to date have had several limitations. They primarily examine flows of bidispersed material, are small in scale, and rely on observations from flume sidewalls, precluding the study of dynamics along the centreline of flows. In this study, a large scale 6.8 m long and 2.1 m wide slope inclined at 30 degrees was used to generate dry tridispersed granular flows with 0.6 m3 of material. The tridisperse mixture consisted of even proportions by mass of 3 mm, 6 mm and 12 mm diameter spherical particles. Replicate tests were conducted to observe flow dynamics and assess methods for sampling along the internal plane of the test deposit. Image analysis techniques were developed to quantify particle size distributions within the deposit. Flume sidewall and internal observations were found to differ significantly from each other, in that side wall observations contained significantly higher proportions of the largest particle size. Additional replicate tests were conducted with saturated material to further examine the impact of pore fluid on segregation. This work will allow for future calibration of both numerical and theoretical models of particle size segregation and ultimately enable better debris flow modelling and mitigation practices.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Particle size segregation is a phenomenon that generates preferential sorting of particles, based on size, in material flows of non-uniform size distribution. Landslide hazards, such as debris flows, involve materials of non-uniform particle sizes and therefore generate flow structures which arise from particle size segregation. The mobility, distal reach and impact forces associated with these natural hazards are influenced by these processes. Understanding the mechanisms of this phenomenon is essential for acquiring accurate input parameters that are needed to model these flows and properly design debris flow barriers and retaining structures. While the dynamics of particle size segregation in flow and deposition have been furthered through studying granular flows, studies to date have had several limitations. They primarily examine flows of bidispersed material, are small in scale, and rely on observations from flume sidewalls, precluding the study of dynamics along the centreline of flows. In this study, a large scale 6.8 m long and 2.1 m wide slope inclined at 30 degrees was used to generate dry tridispersed granular flows with 0.6 m3 of material. The tridisperse mixture consisted of even proportions by mass of 3 mm, 6 mm and 12 mm diameter spherical particles. Replicate tests were conducted to observe flow dynamics and assess methods for sampling along the internal plane of the test deposit. Image analysis techniques were developed to quantify particle size distributions within the deposit. Flume sidewall and internal observations were found to differ significantly from each other, in that side wall observations contained significantly higher proportions of the largest particle size. Additional replicate tests were conducted with saturated material to further examine the impact of pore fluid on segregation. This work will allow for future calibration of both numerical and theoretical models of particle size segregation and ultimately enable better debris flow modelling and mitigation practices.
Rafi, Jalaleddin; Rahman, Mashuqur; Zetterlund, Magnus
Assessment of Rock Fracture Jacking During Grouting: Evaluation of an Analytical Solution Through Cases from Scandinavian Tunneling Projects Conference
6th International Conference on Grouting and Deep Mixing, 2023.
@conference{Conference1_142,
title = {Assessment of Rock Fracture Jacking During Grouting: Evaluation of an Analytical Solution Through Cases from Scandinavian Tunneling Projects},
author = {Jalaleddin Rafi and Mashuqur Rahman and Magnus Zetterlund},
year = {2023},
date = {2023-12-25},
urldate = {2023-12-30},
booktitle = {6th International Conference on Grouting and Deep Mixing},
abstract = {Grouting of rock fractures is one of the main activities in tunnelling through fractured rock, and determination of an optimum grouting pressure is crucial for the success of the project. In this paper, an analytical approach was used to evaluate the performed grouting in a tunnelling project in Sweden. Optimized pressure is a function of the required spread distance of the grout mix while limiting dilation of rock fractures to a certain maximum amount. The proposed approach determines grouting pressure, in conjugation with in-situ rock stresses, to control the dilation of fracture during the grouting process until the grout mix spreads to the required distance, where the grouting is called completed. This analytical approach was used to evaluate both the design concept and the executed grouting work. First, possible dilation of the fractures due to the design pressures and the corresponding spread of grout were estimated. Later, the data from the executed grouting work were evaluated to assess the efficiency of the used pressure and consequences of rock fracture jacking. Finally, the optimized pressure and stop criteria for the studied cases are discussed. It is shown that this analytical approach is beneficial to control rock fracture jacking and spread of grout while improving penetrability and reducing grouting time.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Grouting of rock fractures is one of the main activities in tunnelling through fractured rock, and determination of an optimum grouting pressure is crucial for the success of the project. In this paper, an analytical approach was used to evaluate the performed grouting in a tunnelling project in Sweden. Optimized pressure is a function of the required spread distance of the grout mix while limiting dilation of rock fractures to a certain maximum amount. The proposed approach determines grouting pressure, in conjugation with in-situ rock stresses, to control the dilation of fracture during the grouting process until the grout mix spreads to the required distance, where the grouting is called completed. This analytical approach was used to evaluate both the design concept and the executed grouting work. First, possible dilation of the fractures due to the design pressures and the corresponding spread of grout were estimated. Later, the data from the executed grouting work were evaluated to assess the efficiency of the used pressure and consequences of rock fracture jacking. Finally, the optimized pressure and stop criteria for the studied cases are discussed. It is shown that this analytical approach is beneficial to control rock fracture jacking and spread of grout while improving penetrability and reducing grouting time.
Arenson, Lukas; Brooks, Heather; scott,; Anderson, Scott
Bridging the Pretty Rocks Landslide in Denali National Park Conference
European Conference on Permafrost (EUCOP 6), 2023.
@conference{Conference1,
title = {Bridging the Pretty Rocks Landslide in Denali National Park},
author = {Lukas Arenson and Heather Brooks and scott and Scott Anderson},
doi = {0.52381/EUCOP6.abstracts.1},
year = {2023},
date = {2023-12-15},
urldate = {2023-12-15},
booktitle = {European Conference on Permafrost (EUCOP 6)},
abstract = { In late August 2021, park managers of the Denali National Park in Alaska concluded that they would no longer be able to maintain the park access road along a section known as Pretty Rocks, where the road has been constantly slumping since the 2010s. Most recently, the road dropped by more than 2 cm per day. The geology at the site is complex with rock overlying weaker tuff and clay materials, and frozen colluvium present. This geology and the local permafrost conditions result in the presence of ground ice of varying form and volumetric ice contents. Permafrost degradation is thought to play a role in the increasing rate of deformation of Pretty Rocks Landslide and the parks decided that building a bridge over this active landslide would the best option. To reopen the parks road, a hazard avoidance strategy was chosen; thus, a steel truss bridge is planned to span the landslide. The proposed bridge requires stable foundation conditions and rock cuts for the approaches. Considering that excavating and removing all the ground ice at this location is not feasible it was decided that permafrost conditions being maintained, where present, and used in the bridge foundation and cuts. Therefore, complex three-dimensional numerical modelling was completed to evaluate various foundation design options, including thermosyphons at the east bridge abutment. Three-dimensional modelling was considered essential because the complex geology, permafrost and terrain conditions could not be adequately simplified using two-dimensional models only. We present the results of our thermal models, the final design of the bridge foundation, which includes more than 20 thermosyphons, and the challenges we encountered completing this complex task. In addition, we provide an overview of information from the site investigation that was used for the development of the numerical model, including geotechnical drilling, geophysical investigations, ground temperature measurements, lidar change detection and climate change projections.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In late August 2021, park managers of the Denali National Park in Alaska concluded that they would no longer be able to maintain the park access road along a section known as Pretty Rocks, where the road has been constantly slumping since the 2010s. Most recently, the road dropped by more than 2 cm per day. The geology at the site is complex with rock overlying weaker tuff and clay materials, and frozen colluvium present. This geology and the local permafrost conditions result in the presence of ground ice of varying form and volumetric ice contents. Permafrost degradation is thought to play a role in the increasing rate of deformation of Pretty Rocks Landslide and the parks decided that building a bridge over this active landslide would the best option. To reopen the parks road, a hazard avoidance strategy was chosen; thus, a steel truss bridge is planned to span the landslide. The proposed bridge requires stable foundation conditions and rock cuts for the approaches. Considering that excavating and removing all the ground ice at this location is not feasible it was decided that permafrost conditions being maintained, where present, and used in the bridge foundation and cuts. Therefore, complex three-dimensional numerical modelling was completed to evaluate various foundation design options, including thermosyphons at the east bridge abutment. Three-dimensional modelling was considered essential because the complex geology, permafrost and terrain conditions could not be adequately simplified using two-dimensional models only. We present the results of our thermal models, the final design of the bridge foundation, which includes more than 20 thermosyphons, and the challenges we encountered completing this complex task. In addition, we provide an overview of information from the site investigation that was used for the development of the numerical model, including geotechnical drilling, geophysical investigations, ground temperature measurements, lidar change detection and climate change projections.
Shahnazari, Habib; Kazemi, Mohammad; Basiar, Mohammad
Centrifuge Modeling of Ground Vibrations Mitigation by Inclined Geofoam Barrier Journal Article
In: International Journal of Physical Modelling in Geotechnics, 2023.
@article{journal1,
title = {Centrifuge Modeling of Ground Vibrations Mitigation by Inclined Geofoam Barrier},
author = {Habib Shahnazari and Mohammad Kazemi and Mohammad Basiar},
doi = {10.1680/jphmg.22.00032},
year = {2023},
date = {2023-11-28},
urldate = {2023-11-28},
journal = {International Journal of Physical Modelling in Geotechnics},
abstract = {This paper presents a centrifuge study on the performance of inclined geofoam barriers compared to a vertical geofoam barrier for the mitigation of ground vibrations induced by high-speed railways. Three different barrier inclinations (60°, 90° and 120°) are used in three centrifuge models. Each centrifuge model is tested for seven different frequencies. Therefore, the results of 21 centrifuge tests are reported in this paper. The results show that the barrier efficiency (BE) of inclined barriers is greater than the vertical BE for the points located behind the barrier. However, for a point located before the barrier, the BE reduces by using inclined barriers instead of the vertical barrier. The results also illustrate that the barrier efficiencies for the two inclined barriers used in this research, which have supplementary angles, are almost the same.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper presents a centrifuge study on the performance of inclined geofoam barriers compared to a vertical geofoam barrier for the mitigation of ground vibrations induced by high-speed railways. Three different barrier inclinations (60°, 90° and 120°) are used in three centrifuge models. Each centrifuge model is tested for seven different frequencies. Therefore, the results of 21 centrifuge tests are reported in this paper. The results show that the barrier efficiency (BE) of inclined barriers is greater than the vertical BE for the points located behind the barrier. However, for a point located before the barrier, the BE reduces by using inclined barriers instead of the vertical barrier. The results also illustrate that the barrier efficiencies for the two inclined barriers used in this research, which have supplementary angles, are almost the same.
Ouellet, Susanne; Dettmer, Jan; Karrenbach, Martin; Olivier, Gerrit; Lato, Matthew
Combining Distributed Fibre Optic Sensing With Passive Seismic Interferometry for Advanced Monitoring Applications Conference
JTC1 Workshop: Natural Slopes and Landslides, 2023.
@conference{Conference1,
title = {Combining Distributed Fibre Optic Sensing With Passive Seismic Interferometry for Advanced Monitoring Applications},
author = {Susanne Ouellet and Jan Dettmer and Martin Karrenbach and Gerrit Olivier and Matthew Lato},
year = {2023},
date = {2023-11-17},
urldate = {2023-11-15},
booktitle = {JTC1 Workshop: Natural Slopes and Landslides},
abstract = {Distributed acoustic sensing (DAS) is a fibre optic sensing technology that relies on the backscattering of Rayleigh light waves. Perturbations to the optical fibre attributed to variations in strain or temperature, affect the phase, intensity and polarization of the backscattered light (Masoudi & Newson, 2016). As DAS can be considered as an array of seismic sensors, it is increasingly being used in place of traditional seismic sensors, installed at discrete locations, to monitor physical processes in the subsurface. DAS is unique from other types of distributed fibre optic sensing methods (e.g., Brillouin and Raman based methods to monitor strain and temperature, respectively) in its capability of monitoring tens of kilometers of fibre at kilohertz sampling rates (Muanenda, 2018). This is highly advantageous for linear assets that require real-time monitoring, such as pipelines and transportation corridors. By applying seismic interferometry, relative changes in seismic velocities (dv/v (%)) can be used to monitor structures such as landslides and dams (Mainsant et al., 2012; Planès et al., 2016). By combining dv/v monitoring with DAS, subsurface changes can be detected with unprecedented spatial and temporal resolution, showing promise for early warning applications. Here, we infer dv/v changes to monitor a tailings dam with DAS. The DAS dataset consists of data recorded from a ~120 m section of buried optical fibre recording data over spring and summer of 2021 at a tailings dam in northern Canada. The seismic velocity changes are compared with environmental site parameters including rainfall, pond levels and temperature data.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Distributed acoustic sensing (DAS) is a fibre optic sensing technology that relies on the backscattering of Rayleigh light waves. Perturbations to the optical fibre attributed to variations in strain or temperature, affect the phase, intensity and polarization of the backscattered light (Masoudi & Newson, 2016). As DAS can be considered as an array of seismic sensors, it is increasingly being used in place of traditional seismic sensors, installed at discrete locations, to monitor physical processes in the subsurface. DAS is unique from other types of distributed fibre optic sensing methods (e.g., Brillouin and Raman based methods to monitor strain and temperature, respectively) in its capability of monitoring tens of kilometers of fibre at kilohertz sampling rates (Muanenda, 2018). This is highly advantageous for linear assets that require real-time monitoring, such as pipelines and transportation corridors. By applying seismic interferometry, relative changes in seismic velocities (dv/v (%)) can be used to monitor structures such as landslides and dams (Mainsant et al., 2012; Planès et al., 2016). By combining dv/v monitoring with DAS, subsurface changes can be detected with unprecedented spatial and temporal resolution, showing promise for early warning applications. Here, we infer dv/v changes to monitor a tailings dam with DAS. The DAS dataset consists of data recorded from a ~120 m section of buried optical fibre recording data over spring and summer of 2021 at a tailings dam in northern Canada. The seismic velocity changes are compared with environmental site parameters including rainfall, pond levels and temperature data.
Brown, Alex
Could it Fail? GIS Based Risk Calculation for Geohazards Impacting Linear Infrastructure Conference
20th Annual Technical Forum on Geohazards, 2023.
@conference{Conference1,
title = {Could it Fail? GIS Based Risk Calculation for Geohazards Impacting Linear Infrastructure},
author = {Alex Brown},
year = {2023},
date = {2023-11-16},
urldate = {2023-11-16},
booktitle = {20th Annual Technical Forum on Geohazards},
abstract = {As Geotechnical Asset Management (GAM) has become increasingly important for transportation departments, multiple systems have been implemented for different asset managers of linear infrastructure (railway, pipelines, and state transportation departments). A risk-based approach has been widely adopted, with the overarching calculation of risk equal to the product of the probability of occurrence and the consequence. Consequence is typically defined by the costs of maintenance, user mobility, and user safety, while the calculations of probabilities can vary significantly between asset managers. As part of the development of these management systems, large quantities of data have been collected by transportation departments, railways, and pipeline owners, including lidar imagery, event data, and aerial imagery. Often, these data have been collected without a clear plan for their use in GAM, other than the development of a catalogue of sites. For many asset managers, the next step in progressing their GAM is converting these data into the calculation of risk. BGC Engineering has supported this risk-based approach for multiple linear infrastructure clients for more than 20 years, including more than 80 oil and gas, mining, transportation, and government sector clients. Moreover, BGC has developed an online geographic information system (GIS) capable of hosting hundreds of terabytes of data (lidar, photogrammetry, photographs, climate systems, etc.) and incorporating these data into the calculations of risk across multiple industries. BGC has developed algorithms for the calculation of risk and applied it to nearly 250,000 Oil and Gas pipeline geohazard sites in Canada and the US, including over 50,000 sites in the Appalachian region. The implementation of these algorithms has enabled BGC to support this industry in reducing the number of pipeline geohazard failures by a factor of between 3 and 5. BGC is currently working with 5 US based transportation management agencies to develop similar capabilities for highway infrastructure at corridor and statewide scales.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
As Geotechnical Asset Management (GAM) has become increasingly important for transportation departments, multiple systems have been implemented for different asset managers of linear infrastructure (railway, pipelines, and state transportation departments). A risk-based approach has been widely adopted, with the overarching calculation of risk equal to the product of the probability of occurrence and the consequence. Consequence is typically defined by the costs of maintenance, user mobility, and user safety, while the calculations of probabilities can vary significantly between asset managers. As part of the development of these management systems, large quantities of data have been collected by transportation departments, railways, and pipeline owners, including lidar imagery, event data, and aerial imagery. Often, these data have been collected without a clear plan for their use in GAM, other than the development of a catalogue of sites. For many asset managers, the next step in progressing their GAM is converting these data into the calculation of risk. BGC Engineering has supported this risk-based approach for multiple linear infrastructure clients for more than 20 years, including more than 80 oil and gas, mining, transportation, and government sector clients. Moreover, BGC has developed an online geographic information system (GIS) capable of hosting hundreds of terabytes of data (lidar, photogrammetry, photographs, climate systems, etc.) and incorporating these data into the calculations of risk across multiple industries. BGC has developed algorithms for the calculation of risk and applied it to nearly 250,000 Oil and Gas pipeline geohazard sites in Canada and the US, including over 50,000 sites in the Appalachian region. The implementation of these algorithms has enabled BGC to support this industry in reducing the number of pipeline geohazard failures by a factor of between 3 and 5. BGC is currently working with 5 US based transportation management agencies to develop similar capabilities for highway infrastructure at corridor and statewide scales.
Wong, Colin; Zawadzki, Willy
Emissions Rate Measurement with Flow Modelling to Optimize Landfill Gas Collection from Horizontal Collectors Journal Article
In: Waste Management, vol. 157, pp. 199-209, 2023.
@article{journal1b,
title = {Emissions Rate Measurement with Flow Modelling to Optimize Landfill Gas Collection from Horizontal Collectors},
author = {Colin Wong and Willy Zawadzki},
doi = {10.1016/j.wasman.2022.12.018},
year = {2023},
date = {2023-10-23},
urldate = {2023-10-23},
journal = {Waste Management},
volume = {157},
pages = {199-209},
abstract = {A two-dimensional landfill gas flow model using the FEFLOW numerical code was developed to assess the potential improvement in landfill gas (LFG) collection and the reduction in greenhouse gas emissions at a landfill due to increases in the vacuum of horizontal collectors and/or installation of additional LFG collection infrastructure. A key calibration input parameter for the model, the fugitive methane emission rate from the study area, was measured using the airborne matter mapping method. The measurement showed that, at the time, the methane collection efficiency for the study area was approximately 37 %. The model indicated that increasing the vacuum of the existing collection system by 0.75 kPa could result in an improvement in collection efficiency from 37 % to 49 % within the selected study area. A similar increase of collection efficiency could be obtained by either doubling the number of horizontal collectors on a platform or installing a layer of permeable demolition waste on that level, without an increase in collection system vacuum. Combining the addition of collection infrastructure with an increase in collection system vacuum by 1 kPa was predicted to improve the collection efficiency for the study area to about 74 %.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A two-dimensional landfill gas flow model using the FEFLOW numerical code was developed to assess the potential improvement in landfill gas (LFG) collection and the reduction in greenhouse gas emissions at a landfill due to increases in the vacuum of horizontal collectors and/or installation of additional LFG collection infrastructure. A key calibration input parameter for the model, the fugitive methane emission rate from the study area, was measured using the airborne matter mapping method. The measurement showed that, at the time, the methane collection efficiency for the study area was approximately 37 %. The model indicated that increasing the vacuum of the existing collection system by 0.75 kPa could result in an improvement in collection efficiency from 37 % to 49 % within the selected study area. A similar increase of collection efficiency could be obtained by either doubling the number of horizontal collectors on a platform or installing a layer of permeable demolition waste on that level, without an increase in collection system vacuum. Combining the addition of collection infrastructure with an increase in collection system vacuum by 1 kPa was predicted to improve the collection efficiency for the study area to about 74 %.
Walton, Gabriel; Christiansen, Cole; Kromer, Ryan; Silaev, Artyom
Evaluation of Rockfall Trends at a Sedimentary Rock Cut Near Manitou Springs, Colorado, Using Daily Photogrammetric Monitoring Journal Article
In: Landslides, 2023.
@article{journal1,
title = {Evaluation of Rockfall Trends at a Sedimentary Rock Cut Near Manitou Springs, Colorado, Using Daily Photogrammetric Monitoring},
author = {Gabriel Walton and Cole Christiansen and Ryan Kromer and Artyom Silaev},
doi = {10.1007/s10346-023-02121-8},
year = {2023},
date = {2023-10-16},
urldate = {2023-10-28},
journal = {Landslides},
abstract = {Rockfall remains a prominent hazard for transportation corridors worldwide. Recent studies have shown promising results in resolving the relationships between rockfall activity and triggers, including in some cases detecting precursor activity prior to failure, which could have implications to improving safety and performance of transportation corridors. The aim of this study is to better understand rockfall failure processes and triggers for cut slopes in interbedded sedimentary rock through a long-term study using photogrammetry data with high spatiotemporal frequency. The combination of daily data, high-precision rockfall volume estimation, and 22-month monitoring duration is unique among studies that evaluate rockfall triggers and allows us to derive insights into differences in rockfall triggering between blocks of different volumes. The data collected allowed the relative frequency of rockfalls of different volumes to be well-constrained for volumes ranging from 0.01 m3 up to 76 m3 (the largest event that occurred during the monitoring period). A quantitative comparison between precipitation and rockfall activity established that precipitation was the primary trigger for rockfall at the site, with only 1.4% of 24-h photo intervals without precipitation having at least one rockfall, as compared to 25.0% of photo intervals with precipitation (and 57.1% of photo intervals with at least 5 mm of precipitation). The marginal impact of additional rainfall above 8 mm per 24-h period on rockfall probability was negligible among all rockfalls observed, whereas the probability of the largest rockfalls at the site (> 1 m3) occurring continued to increase as a function of precipitation up to 20 mm per 24-h period. Detailed analysis of change data leading up to the largest (76 m3) rockfall observed illustrated the progressive failure mechanism of the block, including observations of forward toppling motion and smaller precursor rockfalls around its perimeter. This rockfall was also used for a proof-of-concept demonstration of the potential for a spatiotemporal rockfall density metric to be used to help identify areas of potential hazard. Ultimately, the findings from this study contribute to knowledge on rockfall processes outside alpine regions, which have historically been less well-studied.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Rockfall remains a prominent hazard for transportation corridors worldwide. Recent studies have shown promising results in resolving the relationships between rockfall activity and triggers, including in some cases detecting precursor activity prior to failure, which could have implications to improving safety and performance of transportation corridors. The aim of this study is to better understand rockfall failure processes and triggers for cut slopes in interbedded sedimentary rock through a long-term study using photogrammetry data with high spatiotemporal frequency. The combination of daily data, high-precision rockfall volume estimation, and 22-month monitoring duration is unique among studies that evaluate rockfall triggers and allows us to derive insights into differences in rockfall triggering between blocks of different volumes. The data collected allowed the relative frequency of rockfalls of different volumes to be well-constrained for volumes ranging from 0.01 m3 up to 76 m3 (the largest event that occurred during the monitoring period). A quantitative comparison between precipitation and rockfall activity established that precipitation was the primary trigger for rockfall at the site, with only 1.4% of 24-h photo intervals without precipitation having at least one rockfall, as compared to 25.0% of photo intervals with precipitation (and 57.1% of photo intervals with at least 5 mm of precipitation). The marginal impact of additional rainfall above 8 mm per 24-h period on rockfall probability was negligible among all rockfalls observed, whereas the probability of the largest rockfalls at the site (> 1 m3) occurring continued to increase as a function of precipitation up to 20 mm per 24-h period. Detailed analysis of change data leading up to the largest (76 m3) rockfall observed illustrated the progressive failure mechanism of the block, including observations of forward toppling motion and smaller precursor rockfalls around its perimeter. This rockfall was also used for a proof-of-concept demonstration of the potential for a spatiotemporal rockfall density metric to be used to help identify areas of potential hazard. Ultimately, the findings from this study contribute to knowledge on rockfall processes outside alpine regions, which have historically been less well-studied.
Arenson, Lukas
Geohazards in Mountain Environments in Response to a Rapidly Changing Cryosphere and the Role of Geotechnical Engineering Conference
GeoMandu: Geohazards and Geo-Infra Disasters, 2023.
@conference{Conference1,
title = {Geohazards in Mountain Environments in Response to a Rapidly Changing Cryosphere and the Role of Geotechnical Engineering},
author = {Lukas Arenson},
year = {2023},
date = {2023-09-27},
urldate = {2023-09-26},
booktitle = {GeoMandu: Geohazards and Geo-Infra Disasters},
abstract = {Not only in terrains north of 60° latitude, geotechnical designs and geohazard are affected by cold climate, glaciers and permafrost but also many areas around the world are subject to impacts from freezing conditions or are affected by permafrost, in particular within high mountain regions. As climate is changing, historic records may no longer be representative for future behaviour, making designs and geohazard assessments that rely on the past unreliable and difficult. Specifically, the glacial and the periglacial environments are changing at fast and unprecedented rates. These changes in the mountain environments around the world lead, on the one hand, to the disappearance of some hazards, e.g., lack of ice falls in response to rapid glacier retreat, but on the other hand to the creation of new ones, such as instabilities due to glacial debuttressing or increased potential for glacier lake outburst floods, as new proglacial lakes form and mass movement activities increase. In addition, permafrost, which in many mountain regions around the world is typically discontinuous, in spatial terms, and warm, is expected to degrade further and disappear with time, affecting infrastructure foundations and slope stabilities.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Not only in terrains north of 60° latitude, geotechnical designs and geohazard are affected by cold climate, glaciers and permafrost but also many areas around the world are subject to impacts from freezing conditions or are affected by permafrost, in particular within high mountain regions. As climate is changing, historic records may no longer be representative for future behaviour, making designs and geohazard assessments that rely on the past unreliable and difficult. Specifically, the glacial and the periglacial environments are changing at fast and unprecedented rates. These changes in the mountain environments around the world lead, on the one hand, to the disappearance of some hazards, e.g., lack of ice falls in response to rapid glacier retreat, but on the other hand to the creation of new ones, such as instabilities due to glacial debuttressing or increased potential for glacier lake outburst floods, as new proglacial lakes form and mass movement activities increase. In addition, permafrost, which in many mountain regions around the world is typically discontinuous, in spatial terms, and warm, is expected to degrade further and disappear with time, affecting infrastructure foundations and slope stabilities.
Wlodarczyk, Kyle; Davidson, Sarah; Scordo, Elisa; Lau, Carie-Ann
Geomorphic Response of Two Gravel-Bed Rivers to the November 2021 Atmospheric River and Flood Event in British Columbia, Canada: The Role of Sediment Supply Conference
Gravel Bed Rivers 9, 2023.
@conference{Conference1c,
title = {Geomorphic Response of Two Gravel-Bed Rivers to the November 2021 Atmospheric River and Flood Event in British Columbia, Canada: The Role of Sediment Supply},
author = {Kyle Wlodarczyk and Sarah Davidson and Elisa Scordo and Carie-Ann Lau},
year = {2023},
date = {2023-09-26},
urldate = {2023-09-26},
booktitle = {Gravel Bed Rivers 9},
abstract = {Spatial patterns of sediment availability may influence the morphological changes experienced by gravel-bed rivers during extreme flood events. An atmospheric river (AR) in November 2021 brought two days of intense rainfall to southwestern British Columbia (BC), Canada, leading to extreme flooding and landsliding across numerous watersheds in the region. Many channels experienced significant planform changes, including the Coquihalla River and Coldwater River along BC's Coquihalla Highway. The lateral channel instability of these two rivers resulted in severe damage to transportation infrastructure, with bridges and other sections of road left destroyed or inoperable, aiding the near complete isolation of Vancouver, BC by road and rail. Lidar data were collected one week after the flood event in support of engineering design efforts to rebuild the highway and mitigate other nearby infrastructure. We compared the post-flood event lidar to 190 km 2 of available pre-flood event lidar, capturing channel changes in 47 km of the Coquihalla River and 28 km of the Coldwater River, to determine locations of lateral instability within the captured reaches. The locations of large sediment inputs into these two rivers that were triggered by the AR event were mapped and analyzed in conjunction with the lidar comparison to identify relationships between local sediment sources and lateral channel instability. A key finding of this analysis was that the morphological changes that resulted in the most significant damage to linear infrastructure were associated with localized sediment input. Reaches without external sediment supplied were more likely to be laterally stable. Potential morphological impacts from nearby sediment sources should be considered when designing transportation and linear infrastructure in riparian environments, as the sediment supplied from these sources may cause lateral channel instability that impacts structural integrity.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Spatial patterns of sediment availability may influence the morphological changes experienced by gravel-bed rivers during extreme flood events. An atmospheric river (AR) in November 2021 brought two days of intense rainfall to southwestern British Columbia (BC), Canada, leading to extreme flooding and landsliding across numerous watersheds in the region. Many channels experienced significant planform changes, including the Coquihalla River and Coldwater River along BC's Coquihalla Highway. The lateral channel instability of these two rivers resulted in severe damage to transportation infrastructure, with bridges and other sections of road left destroyed or inoperable, aiding the near complete isolation of Vancouver, BC by road and rail. Lidar data were collected one week after the flood event in support of engineering design efforts to rebuild the highway and mitigate other nearby infrastructure. We compared the post-flood event lidar to 190 km 2 of available pre-flood event lidar, capturing channel changes in 47 km of the Coquihalla River and 28 km of the Coldwater River, to determine locations of lateral instability within the captured reaches. The locations of large sediment inputs into these two rivers that were triggered by the AR event were mapped and analyzed in conjunction with the lidar comparison to identify relationships between local sediment sources and lateral channel instability. A key finding of this analysis was that the morphological changes that resulted in the most significant damage to linear infrastructure were associated with localized sediment input. Reaches without external sediment supplied were more likely to be laterally stable. Potential morphological impacts from nearby sediment sources should be considered when designing transportation and linear infrastructure in riparian environments, as the sediment supplied from these sources may cause lateral channel instability that impacts structural integrity.
Bauman, Paul
Geophysical Water Exploration and Self-Supply in Post Conflict Uganda Conference
GeoConvention, 2023.
@conference{Conference1,
title = {Geophysical Water Exploration and Self-Supply in Post Conflict Uganda},
author = {Paul Bauman},
year = {2023},
date = {2023-09-25},
urldate = {2023-09-26},
booktitle = {GeoConvention},
abstract = {From 1986 until 2008, Joseph Kony lead the Lord’s Resistance Army (LRA) in an insurgency in Northern Uganda, largely focused in the Acholi speaking sub-region known as Acholiland. Beginning in 1996, the Government of Uganda concentrated the approximately two million rural Acholi population into “protected villages.” Meanwhile, the war against Kony, his approximately 3,000 rebels, and approximately 65,000 child soldiers was prosecuted. The “protected villages” were essentially concentration camps with the highest mortality rates in the world. In 2008, Acholi people began returning to their abandoned and destroyed villages. The reestablishment of safe and accessible village water supplies remains a regional need. At the same time, marginalized Acholi youth returning as child soldiers, human beasts of burden, internally displaced persons, or simply as young people lacking education were and remain in need of developing livelihoods. This talk will describe the training of Acholi people to begin the redevelopment of their water supplies, and the technically focused water exploration and well rehabilitation programs that followed. The talk will describe short training programs in 2015 and 2016, and water supply development campaigns that were executed in 2018 and 2023. Water exploration was carried out in search of crystalline basement aquifers. Geoelectrical and terrain conductivity methods were used for surface exploration. Borehole terrain conductivity and magnetic susceptibility logging were used to guide and interpret the surface exploration program. An intensive aqueous geochemical sampling program was carried out that included major and trace metal ion analyses, stable isotope analyses, and a novel field E. coli bacteria analysis method. A simple but highly effective hand pump assessment method was introduced that is a significant improvement over evaluation criteria currently in use. To date, safe and accessible water has been made available to approximately 15,000 rural inhabitants in 30 villages, 2000 primary school students; and one major health clinic.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
From 1986 until 2008, Joseph Kony lead the Lord’s Resistance Army (LRA) in an insurgency in Northern Uganda, largely focused in the Acholi speaking sub-region known as Acholiland. Beginning in 1996, the Government of Uganda concentrated the approximately two million rural Acholi population into “protected villages.” Meanwhile, the war against Kony, his approximately 3,000 rebels, and approximately 65,000 child soldiers was prosecuted. The “protected villages” were essentially concentration camps with the highest mortality rates in the world. In 2008, Acholi people began returning to their abandoned and destroyed villages. The reestablishment of safe and accessible village water supplies remains a regional need. At the same time, marginalized Acholi youth returning as child soldiers, human beasts of burden, internally displaced persons, or simply as young people lacking education were and remain in need of developing livelihoods. This talk will describe the training of Acholi people to begin the redevelopment of their water supplies, and the technically focused water exploration and well rehabilitation programs that followed. The talk will describe short training programs in 2015 and 2016, and water supply development campaigns that were executed in 2018 and 2023. Water exploration was carried out in search of crystalline basement aquifers. Geoelectrical and terrain conductivity methods were used for surface exploration. Borehole terrain conductivity and magnetic susceptibility logging were used to guide and interpret the surface exploration program. An intensive aqueous geochemical sampling program was carried out that included major and trace metal ion analyses, stable isotope analyses, and a novel field E. coli bacteria analysis method. A simple but highly effective hand pump assessment method was introduced that is a significant improvement over evaluation criteria currently in use. To date, safe and accessible water has been made available to approximately 15,000 rural inhabitants in 30 villages, 2000 primary school students; and one major health clinic.
O'Connell, Daniel; Turner, Jamey
Hosgri Fault Transpressional Slip Rates Reproduce Observed Central California Coast Uplift Rates Journal Article
In: The Seismic Record, vol. 3, no. 3, pp. 182-193, 2023.
@article{journal1,
title = {Hosgri Fault Transpressional Slip Rates Reproduce Observed Central California Coast Uplift Rates},
author = {Daniel O'Connell and Jamey Turner},
doi = {10.1785/0320220047},
year = {2023},
date = {2023-09-06},
urldate = {2023-09-06},
journal = {The Seismic Record},
volume = {3},
number = {3},
pages = {182-193},
abstract = {Coastal uplift is a common feature of Pacific Rim tectonic deformation. The 1989 Mw 7.0 Loma Prieta earthquake illustrated that reverse‐oblique slip on a transpressive segment of the predominantly horizontal slip San Andreas transform fault produces coastal uplift. In west‐central California the 400 km long San Gregorio‐Hosgri coastal fault system of near‐vertical to steeply northeast‐dipping, reverse‐oblique, dextral strike‐slip faults also contribute to coastal uplift. Published southern Hosgri fault dextral slip rates are ∼4× reverse rates. Viscoelastic deformation modeling using published transpressional slip rates along the southern Hosgri fault reproduces observed emergent marine terrace uplift rates, offshore Hosgri fault deformation morphology, and crustal structure from San Luis Obispo Bay to Estero Bay. Our coastal uplift rate modeling is constrained by a unique combination of measurements: (1) offshore reverse‐ and strike‐slip Hosgri fault zone (HFZ) slip rates, and (2) ≤125 ka onshore emergent terrace uplift rates adjacent to the HFZ. The previously proposed conceptual rigid block models of the southern central California coast (CCC) invoke local onshore thrust or reverse faults to explain coastal uplift. Observed transpressional offshore Hosgri fault deformation rates alone rigorously reproduce observed coastal uplift rates},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Coastal uplift is a common feature of Pacific Rim tectonic deformation. The 1989 Mw 7.0 Loma Prieta earthquake illustrated that reverse‐oblique slip on a transpressive segment of the predominantly horizontal slip San Andreas transform fault produces coastal uplift. In west‐central California the 400 km long San Gregorio‐Hosgri coastal fault system of near‐vertical to steeply northeast‐dipping, reverse‐oblique, dextral strike‐slip faults also contribute to coastal uplift. Published southern Hosgri fault dextral slip rates are ∼4× reverse rates. Viscoelastic deformation modeling using published transpressional slip rates along the southern Hosgri fault reproduces observed emergent marine terrace uplift rates, offshore Hosgri fault deformation morphology, and crustal structure from San Luis Obispo Bay to Estero Bay. Our coastal uplift rate modeling is constrained by a unique combination of measurements: (1) offshore reverse‐ and strike‐slip Hosgri fault zone (HFZ) slip rates, and (2) ≤125 ka onshore emergent terrace uplift rates adjacent to the HFZ. The previously proposed conceptual rigid block models of the southern central California coast (CCC) invoke local onshore thrust or reverse faults to explain coastal uplift. Observed transpressional offshore Hosgri fault deformation rates alone rigorously reproduce observed coastal uplift rates
Atwood, Abra; Hille, Madeline; Clark, Marin; Rengers, Francis; Ntarlagiannis, Dimitrios; Townsend, Kirk; West, Joshua
Importance of Subsurface Water for Hydrological Response During Storms in a Post-Wildfire Bedrock Landscape Journal Article
In: Nature Communications, vol. 14, 2023.
@article{journal1,
title = {Importance of Subsurface Water for Hydrological Response During Storms in a Post-Wildfire Bedrock Landscape},
author = {Abra Atwood and Madeline Hille and Marin Clark and Francis Rengers and Dimitrios Ntarlagiannis and Kirk Townsend and Joshua West},
doi = {10.1038/s41467-023-39095-z},
year = {2023},
date = {2023-08-18},
urldate = {2023-08-18},
journal = {Nature Communications},
volume = {14},
abstract = {Wildfire alters the hydrologic cycle, with important implications for water supply and hazards including flooding and debris flows. In this study we use a combination of electrical resistivity and stable water isotope analyses to investigate the hydrologic response during storms in three catchments: one unburned and two burned during the 2020 Bobcat Fire in the San Gabriel Mountains, California, USA. Electrical resistivity imaging shows that in the burned catchments, rainfall infiltrated into the weathered bedrock and persisted. Stormflow isotope data indicate that the amount of mixing of surface and subsurface water during storms was similar in all catchments, despite higher streamflow post-fire. Therefore, both surface runoff and infiltration likely increased in tandem. These results suggest that the hydrologic response to storms in post-fire environments is dynamic and involves more surface-subsurface exchange than previously conceptualized, which has important implications for vegetation regrowth and post-fire landslide hazards for years following wildfire.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wildfire alters the hydrologic cycle, with important implications for water supply and hazards including flooding and debris flows. In this study we use a combination of electrical resistivity and stable water isotope analyses to investigate the hydrologic response during storms in three catchments: one unburned and two burned during the 2020 Bobcat Fire in the San Gabriel Mountains, California, USA. Electrical resistivity imaging shows that in the burned catchments, rainfall infiltrated into the weathered bedrock and persisted. Stormflow isotope data indicate that the amount of mixing of surface and subsurface water during storms was similar in all catchments, despite higher streamflow post-fire. Therefore, both surface runoff and infiltration likely increased in tandem. These results suggest that the hydrologic response to storms in post-fire environments is dynamic and involves more surface-subsurface exchange than previously conceptualized, which has important implications for vegetation regrowth and post-fire landslide hazards for years following wildfire.
de Velder, S; Massey, Christopher; Brideau, Marc-Andre; Lukovic, Biljana; Morgenstern, R; Tonswend, D; Rosser, B
Including the Impact of Climate Change in Quantitative Risk Analysis: An Example from Kaikōura, New Zealand Conference
JTC1 Workshop: Impact of global changes on landslide hazard and risk, 2023.
@conference{Conference1,
title = {Including the Impact of Climate Change in Quantitative Risk Analysis: An Example from Kaikōura, New Zealand},
author = {S de Velder and Christopher Massey and Marc-Andre Brideau and Biljana Lukovic and R Morgenstern and D Tonswend and B Rosser},
year = {2023},
date = {2023-08-18},
urldate = {2023-08-18},
booktitle = {JTC1 Workshop: Impact of global changes on landslide hazard and risk},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Reeder, Philip; Jol, Harry; Freund, Richard; McClymont, Alastair; Bauman, Paul
Investigations at the Heereskraftfahrpark (HKP) 562 Forced-Labor Camp in Vilnius, Lithuania Journal Article
In: Heritage, vol. 6, no. 1, pp. 466-482, 2023.
@article{journal1c,
title = {Investigations at the Heereskraftfahrpark (HKP) 562 Forced-Labor Camp in Vilnius, Lithuania},
author = {Philip Reeder and Harry Jol and Richard Freund and Alastair McClymont and Paul Bauman},
doi = {10.3390/heritage6010024},
year = {2023},
date = {2023-08-18},
urldate = {2023-08-18},
journal = {Heritage},
volume = {6},
number = {1},
pages = {466-482},
abstract = {This research, examining the site of the HKP Forced-Labor Camp in Vilnius, Lithuania, located and better defined the characteristics and remaining features of the 1944 camp. There were four over-arching objectives for this research. First, to find the entrance into the principal hiding place where Jews interned in the camp took refuge just before the camp’s liquidation by the Nazis and their local collaborators. Next, find the location of the burial trench(es) where Jewish prisoners who were found in hiding were murdered and initially buried. Next, to find the mass-burial site where Jewish survivors reburied the remains from the trench(es). Lastly, to locate any other evidence related to the murder of Jews at the HKP 562 site. Ground-Penetrating Radar (GPR) found the principal hiding place in the basement of Building 2. Electrical Resistivity Tomography (ERT) discovered the two trenches where camp inhabitants who were shot on-site during liquidation were first buried. ERT also found the location of the mass grave that holds the reburied remains from the trenches. Bullet-scarred walls near the burial trenches indicate where the Jews were shot on-site. This research solved one of the thousands of unknowns about the Holocaust, using geoscience to uncover forgotten and hidden history. The materials and methodologies used in this research can be applied in uncovering this history at thousands of other Holocaust and genocide sites worldwide.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This research, examining the site of the HKP Forced-Labor Camp in Vilnius, Lithuania, located and better defined the characteristics and remaining features of the 1944 camp. There were four over-arching objectives for this research. First, to find the entrance into the principal hiding place where Jews interned in the camp took refuge just before the camp’s liquidation by the Nazis and their local collaborators. Next, find the location of the burial trench(es) where Jewish prisoners who were found in hiding were murdered and initially buried. Next, to find the mass-burial site where Jewish survivors reburied the remains from the trench(es). Lastly, to locate any other evidence related to the murder of Jews at the HKP 562 site. Ground-Penetrating Radar (GPR) found the principal hiding place in the basement of Building 2. Electrical Resistivity Tomography (ERT) discovered the two trenches where camp inhabitants who were shot on-site during liquidation were first buried. ERT also found the location of the mass grave that holds the reburied remains from the trenches. Bullet-scarred walls near the burial trenches indicate where the Jews were shot on-site. This research solved one of the thousands of unknowns about the Holocaust, using geoscience to uncover forgotten and hidden history. The materials and methodologies used in this research can be applied in uncovering this history at thousands of other Holocaust and genocide sites worldwide.
Verma, Priyesh; Wijewickreme, Dharma
Laboratory Assessment of the Effect of Vibro-Replacement Ground Improvement on the Mechanical Response of Natural Silt Journal Article
In: Soil Dynamics and Earthquake Engineering, vol. 173, 2023.
@article{journal1,
title = {Laboratory Assessment of the Effect of Vibro-Replacement Ground Improvement on the Mechanical Response of Natural Silt},
author = {Priyesh Verma and Dharma Wijewickreme},
doi = {10.1016/j.soildyn.2023.108059},
year = {2023},
date = {2023-07-16},
urldate = {2023-07-14},
journal = {Soil Dynamics and Earthquake Engineering},
volume = {173},
abstract = {The effect of vibro-replacement ground improvement on the mechanical response of a low-plastic silt was examined using constant-volume monotonic and cyclic direct simple shear (DSS) testing. The silt samples representing “pre-improvement”, “post-improvement”, “post-improvement-aged” phases were retrieved from the field for testing. The pre- and post-improvement silt specimens consolidated to in-situ stress state, under constant-volume monotonic DSS shearing, displayed no strain-softening. Cyclic-mobility type strain accumulation with a stress-history-normalizable response was noted when pre- and post-improvement silt specimens were tested under constant-volume cyclic DSS loading, in spite of the ground improvement imparted in the latter case. In contrast, the post-improvement-aged silt specimens at in-situ stress state displayed a dilative strain hardening response. Under similar cyclic stress ratios, the rate of build-up of excess pore water pressure with increasing number of loading cycles was found to be least for the post-improvement-aged silt specimens when compared with pre- and post-improvement cases. As such, the cyclic resistance ratio of the post-improvement-aged silt specimens were significantly higher when compared with those from pre- and post-improvement silt specimens. These findings also highlight the importance of understanding the effects of vibro-replacement on the soil fabric/microstructure especially considering the time elapsed since the application of ground improvement.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The effect of vibro-replacement ground improvement on the mechanical response of a low-plastic silt was examined using constant-volume monotonic and cyclic direct simple shear (DSS) testing. The silt samples representing “pre-improvement”, “post-improvement”, “post-improvement-aged” phases were retrieved from the field for testing. The pre- and post-improvement silt specimens consolidated to in-situ stress state, under constant-volume monotonic DSS shearing, displayed no strain-softening. Cyclic-mobility type strain accumulation with a stress-history-normalizable response was noted when pre- and post-improvement silt specimens were tested under constant-volume cyclic DSS loading, in spite of the ground improvement imparted in the latter case. In contrast, the post-improvement-aged silt specimens at in-situ stress state displayed a dilative strain hardening response. Under similar cyclic stress ratios, the rate of build-up of excess pore water pressure with increasing number of loading cycles was found to be least for the post-improvement-aged silt specimens when compared with pre- and post-improvement cases. As such, the cyclic resistance ratio of the post-improvement-aged silt specimens were significantly higher when compared with those from pre- and post-improvement silt specimens. These findings also highlight the importance of understanding the effects of vibro-replacement on the soil fabric/microstructure especially considering the time elapsed since the application of ground improvement.
Bullard, Gemma; Mulligan, Ryan; Take, Andy
Landslide Tsunamis: Exploring Momentum Transfer to Waves Generated by a Range of Materials With different Mobility Impacting Water Journal Article
In: Landslides, 2023.
@article{journal1,
title = {Landslide Tsunamis: Exploring Momentum Transfer to Waves Generated by a Range of Materials With different Mobility Impacting Water},
author = {Gemma Bullard and Ryan Mulligan and Andy Take},
doi = {10.1007/s10346-023-02126-3},
year = {2023},
date = {2023-07-15},
urldate = {2023-07-15},
journal = {Landslides},
abstract = {At impact with water, the velocity and thickness of a landslide are the key factors that govern momentum transfer and wave generation. These properties are not only a function of the size of the slide, but also a function of the landslide material, grain size, pore fluid, and other rheological parameters. The objective of this study is to determine the amplitude of waves generated from realistic landslides composed of both granular material and pore fluid in comparison with the waves generated by end-member landslides composed of only dry granular material or only fluid. To achieve this, laboratory experiments are conducted in a large-scale landslide flume and observations are collected using high-speed digital cameras and wave probes. Different source materials consisting of dry granular material, saturated granular material, and water are released down the landslide slope into the reservoir to generate impulse waves. The waves are analyzed to determine the amplitude and shape, and the effective time and length scales over which each landslide generates a wave. The observations are used to develop a mobility factor for all three landslide types based on the linear relationship between the length of forcing and the time of wave release. The measurements are compared to a predictive momentum-based relationship, and a modified equation is developed to account for the bulk mobility of the landslide. The improved equation can be applied to predict the maximum wave amplitude generated by a wide range of conditions for realistic landslides.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
At impact with water, the velocity and thickness of a landslide are the key factors that govern momentum transfer and wave generation. These properties are not only a function of the size of the slide, but also a function of the landslide material, grain size, pore fluid, and other rheological parameters. The objective of this study is to determine the amplitude of waves generated from realistic landslides composed of both granular material and pore fluid in comparison with the waves generated by end-member landslides composed of only dry granular material or only fluid. To achieve this, laboratory experiments are conducted in a large-scale landslide flume and observations are collected using high-speed digital cameras and wave probes. Different source materials consisting of dry granular material, saturated granular material, and water are released down the landslide slope into the reservoir to generate impulse waves. The waves are analyzed to determine the amplitude and shape, and the effective time and length scales over which each landslide generates a wave. The observations are used to develop a mobility factor for all three landslide types based on the linear relationship between the length of forcing and the time of wave release. The measurements are compared to a predictive momentum-based relationship, and a modified equation is developed to account for the bulk mobility of the landslide. The improved equation can be applied to predict the maximum wave amplitude generated by a wide range of conditions for realistic landslides.
Martin-Vide, Juan; Bateman, Allen; Berenguer, Marc; Campillo, Arnau Amengual M; Corral, C; Llasat-Boija, Maria; Gomez, S; Marin-Esteve, Blanca; Nunez-Gonzalez, Francisco; Prats-Punti, A; Ruiz-Carulla, Roger
Large Wood Debris that Clogged Bridges Followed by a Sudden Release. The 2019 Flash Flood in Catalonia Journal Article
In: Journal of Hydrology: Regional Studies, vol. 47, 2023.
@article{journal1_41,
title = {Large Wood Debris that Clogged Bridges Followed by a Sudden Release. The 2019 Flash Flood in Catalonia},
author = {Juan Martin-Vide and Allen Bateman and Marc Berenguer and Arnau Amengual M Campillo and C Corral and Maria Llasat-Boija and S Gomez and Blanca Marin-Esteve and Francisco Nunez-Gonzalez and A Prats-Punti and Roger Ruiz-Carulla},
doi = {10.1016/j.ejrh.2023.101348},
year = {2023},
date = {2023-07-13},
urldate = {2023-07-01},
journal = {Journal of Hydrology: Regional Studies},
volume = {47},
abstract = {Study region: Francolí River (Catalonia, Iberian Peninsula). Study focus: The aim is the reconstruction of the October 2019 flash flood, that was documented through extensive field work: rainfall (300 mm in just a few hours), flood marks, times of flood passage and witnesses' snapshots and reports, channel changes, log drift (20,000 trees) and woody debris at bridges, as well as large damage and six fatalities. The methods are: hydrological model built for the rainfall-runoff in the basin and the flood routing in the river, use of hydraulic principles such as flow at waterfalls, flow against obstacles (trees), etc. and finally 1D/2D free surface numerical models. New hydrological insights: The uppermost 100 km2 produced discharges of 700 m3/s (up to 50 m3/s/km2, locally). Three bridges failed, but their cascading failure (when one failure triggers the next one downstream) was not proved. The main channel widened more than 10 times, dragging away soil and vegetation like a bulldozer. The resulting large wood debris that clogged two bridges worsened the inundation. An anomalous flow downstream, probably a surge of around 1090 m3/s, due to the failure of a woody jam at a narrow bridge, took two lives. Water Authority is now warning flood planners that vegetated, torrential basins may cause catastrophic floods in the valley towns, if their narrow bridges are sensitive to woody debris.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Study region: Francolí River (Catalonia, Iberian Peninsula). Study focus: The aim is the reconstruction of the October 2019 flash flood, that was documented through extensive field work: rainfall (300 mm in just a few hours), flood marks, times of flood passage and witnesses' snapshots and reports, channel changes, log drift (20,000 trees) and woody debris at bridges, as well as large damage and six fatalities. The methods are: hydrological model built for the rainfall-runoff in the basin and the flood routing in the river, use of hydraulic principles such as flow at waterfalls, flow against obstacles (trees), etc. and finally 1D/2D free surface numerical models. New hydrological insights: The uppermost 100 km2 produced discharges of 700 m3/s (up to 50 m3/s/km2, locally). Three bridges failed, but their cascading failure (when one failure triggers the next one downstream) was not proved. The main channel widened more than 10 times, dragging away soil and vegetation like a bulldozer. The resulting large wood debris that clogged two bridges worsened the inundation. An anomalous flow downstream, probably a surge of around 1090 m3/s, due to the failure of a woody jam at a narrow bridge, took two lives. Water Authority is now warning flood planners that vegetated, torrential basins may cause catastrophic floods in the valley towns, if their narrow bridges are sensitive to woody debris.
Amatya, Pukar; Scheip, Corey; Deprez, Aline; Malet, Jean-Philippe; Slaughter, Stephen; Handwerger, Alexander; Emberson, Robert; Kirschbaum, Dalia; Jean-Baptiste, Julie; Huang, Mong-Han; Clark, Marin; Zekkos, Dimitrios; Huang, Jhih-Rou; Pacini, Fabrizio; Boissier, Euguerran
In: Natural Hazards, 2023.
@article{journal1,
title = {Learnings From Rapid Response Efforts to Remotely Detect Landslides Triggered by the August 2021 Nippes Earthquake and Tropical Storm Grace in Haiti},
author = {Pukar Amatya and Corey Scheip and Aline Deprez and Jean-Philippe Malet and Stephen Slaughter and Alexander Handwerger and Robert Emberson and Dalia Kirschbaum and Julie Jean-Baptiste and Mong-Han Huang and Marin Clark and Dimitrios Zekkos and Jhih-Rou Huang and Fabrizio Pacini and Euguerran Boissier},
doi = {10.1007/s11069-023-06096-6},
year = {2023},
date = {2023-07-11},
urldate = {2023-07-01},
journal = {Natural Hazards},
abstract = {On August 14, 2021, a Mw 7.2 earthquake struck the Tiburon Peninsula of western Haiti triggering thousands of landslides. Three days after the earthquake on August 17, 2021, Tropical Storm Grace crossed shallow waters offshore of southern Haiti triggering more landslides worsening the situation. In the aftermath of these events, several organizations with disaster response capabilities or programs activated to provide information on the location of landslides to first responders on the ground. Utilizing remote sensing to support rapid response, one organization manually mapped initiation point of landslides and three automatically detected landslides. The 2021 Haiti event also provided a unique opportunity to test different automated landslide detection methods that utilized both SAR and optical data in a rapid response scenario where rapid situational awareness was critical. As the methods used are highly replicable, the main goal of this study is to summarize the landslide rapid response products released by the organizations, detection methods, quantify accuracy and provide guidelines on how some of the shortcomings encountered in this effort might be addressed in the future. To support this validation, a manually mapped polygon-based landslide inventory covering the entire affected area was created and is also released through this effort.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
On August 14, 2021, a Mw 7.2 earthquake struck the Tiburon Peninsula of western Haiti triggering thousands of landslides. Three days after the earthquake on August 17, 2021, Tropical Storm Grace crossed shallow waters offshore of southern Haiti triggering more landslides worsening the situation. In the aftermath of these events, several organizations with disaster response capabilities or programs activated to provide information on the location of landslides to first responders on the ground. Utilizing remote sensing to support rapid response, one organization manually mapped initiation point of landslides and three automatically detected landslides. The 2021 Haiti event also provided a unique opportunity to test different automated landslide detection methods that utilized both SAR and optical data in a rapid response scenario where rapid situational awareness was critical. As the methods used are highly replicable, the main goal of this study is to summarize the landslide rapid response products released by the organizations, detection methods, quantify accuracy and provide guidelines on how some of the shortcomings encountered in this effort might be addressed in the future. To support this validation, a manually mapped polygon-based landslide inventory covering the entire affected area was created and is also released through this effort.
Busslinger, Matthias; Jakob, Matthias; Singer, Richard; Calder, Ryan
Log Crib Check Dam Performance Under Multiple Debris-Flow Loadings — East Gate landslide, British Columbia, Canada Conference
8th International Conference on Debris Flow Hazard Mitigation, 2023.
@conference{Conference1,
title = {Log Crib Check Dam Performance Under Multiple Debris-Flow Loadings — East Gate landslide, British Columbia, Canada},
author = {Matthias Busslinger and Matthias Jakob and Richard Singer and Ryan Calder},
year = {2023},
date = {2023-07-10},
urldate = {2023-07-01},
booktitle = {8th International Conference on Debris Flow Hazard Mitigation},
abstract = {Check dams are used in gullies to prevent vertical downcutting of the thalweg. Check dams built as log crib structures are common in steep creeks prone to floods or debris floods. Recent experience with performance of log crib check dams subject to debris flow loadings is less common, as those check dams are often built with reinforced concrete, steel or masonry. This paper summarizes our experience with six log crib check dams built in a gully at East Gate Landslide, between Revelstoke and Golden, BC, Canada. The log crib check dams are subjected to multiple debris flow events every year. The project started as a pilot study and the design is adjusted before the next construction season, based on performance experience with previously built structures. Key findings are presented in this paper.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Check dams are used in gullies to prevent vertical downcutting of the thalweg. Check dams built as log crib structures are common in steep creeks prone to floods or debris floods. Recent experience with performance of log crib check dams subject to debris flow loadings is less common, as those check dams are often built with reinforced concrete, steel or masonry. This paper summarizes our experience with six log crib check dams built in a gully at East Gate Landslide, between Revelstoke and Golden, BC, Canada. The log crib check dams are subjected to multiple debris flow events every year. The project started as a pilot study and the design is adjusted before the next construction season, based on performance experience with previously built structures. Key findings are presented in this paper.
Koenig, Cassandra; Hilbich, Christin; Hauck, Christian; Wainstein, Pablo; Aaron, Jordan; Pastore, Silvio; Arenson, Lukas
Modelling Ground-Ice Degradation Within the Bermejo Rock Glacier, Central Argentina Conference
6th European Conference on Permafrost (EUCOP 6), 2023.
@conference{Conference1,
title = {Modelling Ground-Ice Degradation Within the Bermejo Rock Glacier, Central Argentina},
author = {Cassandra Koenig and Christin Hilbich and Christian Hauck and Pablo Wainstein and Jordan Aaron and Silvio Pastore and Lukas Arenson},
doi = {0.52381/EUCOP6.abstracts.1},
year = {2023},
date = {2023-06-17},
urldate = {2023-06-17},
booktitle = {6th European Conference on Permafrost (EUCOP 6)},
abstract = {The hydrological contribution from degrading mountain permafrost under climate change in the Central Andes is poorly understood. However, knowledge on thermal and hydrologic feedbacks that influence water availability in this region can be facilitated using numerical cryo-hydrogeology models capable of simulating complex permafrost degradation processes. Such models are often restricted to hypothetical environments due to scarce ground-based data from high altitudes and from periglacial regions of South America in general. The resultant lack of physically representative case studies consequently limits the ability of such models to quantitatively assess possible impacts of climate warming on hydrology, such as contributions to runoff from thawing ground-ice. We present a conceptual model and numerical build for the Bermejo Rock Glacier, located in the Argentinian Andes at approximately El. 4,500 m. The presented model is a refinement of an existing regional numerical model previously developed for a hypothetical mountain slope in the High Andes (up to El. 6,000 m) using characteristic topo-climatic boundaries and bulk geologic properties. The refined model incorporates results from geophysical investigations completed across the 0.5 km2 rock glacier and water flow measurements collected at its front. Electrical resistivity tomography and refraction seismic tomography surveys on the landform informed initial permafrost distribution and ground-ice contents in the model, which varied from ice-free to potentially ice-rich conditions. Discharge measured in front of the landform ranged between 30-155 L/s and represents the combined runoff of upstream meltwater and potential contribution from ground-ice thaw. Future model simulations will investigate the possible contribution to this observed runoff from degrading ground-ice, considering the current distribution of permafrost and possible degradation scenarios.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The hydrological contribution from degrading mountain permafrost under climate change in the Central Andes is poorly understood. However, knowledge on thermal and hydrologic feedbacks that influence water availability in this region can be facilitated using numerical cryo-hydrogeology models capable of simulating complex permafrost degradation processes. Such models are often restricted to hypothetical environments due to scarce ground-based data from high altitudes and from periglacial regions of South America in general. The resultant lack of physically representative case studies consequently limits the ability of such models to quantitatively assess possible impacts of climate warming on hydrology, such as contributions to runoff from thawing ground-ice. We present a conceptual model and numerical build for the Bermejo Rock Glacier, located in the Argentinian Andes at approximately El. 4,500 m. The presented model is a refinement of an existing regional numerical model previously developed for a hypothetical mountain slope in the High Andes (up to El. 6,000 m) using characteristic topo-climatic boundaries and bulk geologic properties. The refined model incorporates results from geophysical investigations completed across the 0.5 km2 rock glacier and water flow measurements collected at its front. Electrical resistivity tomography and refraction seismic tomography surveys on the landform informed initial permafrost distribution and ground-ice contents in the model, which varied from ice-free to potentially ice-rich conditions. Discharge measured in front of the landform ranged between 30-155 L/s and represents the combined runoff of upstream meltwater and potential contribution from ground-ice thaw. Future model simulations will investigate the possible contribution to this observed runoff from degrading ground-ice, considering the current distribution of permafrost and possible degradation scenarios.
Ortis, Emily; Waggott, Tim; Shih, Evan; Gauthier, Dave; Fournier, Chad
Management of Geohazard Personnel Safety for Working in Challenging Terrain Conference
International Pipeline Pigging & Integrity Management Conference, 2023.
@conference{Conference1d,
title = {Management of Geohazard Personnel Safety for Working in Challenging Terrain},
author = {Emily Ortis and Tim Waggott and Evan Shih and Dave Gauthier and Chad Fournier},
year = {2023},
date = {2023-06-17},
urldate = {2023-06-17},
booktitle = {International Pipeline Pigging & Integrity Management Conference},
abstract = {Pacific Northern Gas Ltd. (PNG) owns and operates sweet dry natural gas systems with service extending from Prince Rupert on the British Columbia West Coast to the northeast of the province in the towns of Fort St. John, Dawson Creek, and Tumbler Ridge. PNG’s transmission system operates at high pressures and traverses through one of the most rugged and challenging terrains in North America, with unique weather and geohazard challenges. There has been an increased focus on the integrity and maintenance of PNG’s assets to ensure a safe and reliable energy supply to the communities. This has led to a considerable increase in the scale and size of PNG’s in-line inspection (ILI) program and, consequently, the associated field activities (e.g., ILI runs, pig barrel modifications, integrity digs, regular maintenance and system betterment projects, etc.) on the pipeline system. This requires field operations in proximity to geohazards and potentially unstable terrain, posing a significant personnel safety risk to the field crews. This presented an opportunity for the development of a management tool to support planning and field-level safety decisions. A Geohazard Situational Awareness Tool has been developed in collaboration with BGC Engineering (BGC) to manage the identified field safety risks during the construction season. This tool is based on the PNG’s baseline geohazard assessment findings, more specifically, earth and rock slope hazards, debris flow and debris flood hazard crossings, and hydrological hazards of river crossings and rivers in close proximity to the PNG right of way. This tool provides automatic and semi-automatic daily recommendations on the geohazard safety risks based on predictions supported by weather data and hindcasting/forecasting. This tool enables PNG to make field-level risk-based decisions about short-term fieldwork planning and execution to ensure the safe completion of the associated field activities. This article will present PNG and BGC’s challenges and successes in developing and implementing this pioneer solution for managing identified geohazard risks to personnel safety during the fieldwork season. The intent of this paper is to ensure other operators are aware of the available options to manage personnel safety for working in high-risk geohazard terrains.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Pacific Northern Gas Ltd. (PNG) owns and operates sweet dry natural gas systems with service extending from Prince Rupert on the British Columbia West Coast to the northeast of the province in the towns of Fort St. John, Dawson Creek, and Tumbler Ridge. PNG’s transmission system operates at high pressures and traverses through one of the most rugged and challenging terrains in North America, with unique weather and geohazard challenges. There has been an increased focus on the integrity and maintenance of PNG’s assets to ensure a safe and reliable energy supply to the communities. This has led to a considerable increase in the scale and size of PNG’s in-line inspection (ILI) program and, consequently, the associated field activities (e.g., ILI runs, pig barrel modifications, integrity digs, regular maintenance and system betterment projects, etc.) on the pipeline system. This requires field operations in proximity to geohazards and potentially unstable terrain, posing a significant personnel safety risk to the field crews. This presented an opportunity for the development of a management tool to support planning and field-level safety decisions. A Geohazard Situational Awareness Tool has been developed in collaboration with BGC Engineering (BGC) to manage the identified field safety risks during the construction season. This tool is based on the PNG’s baseline geohazard assessment findings, more specifically, earth and rock slope hazards, debris flow and debris flood hazard crossings, and hydrological hazards of river crossings and rivers in close proximity to the PNG right of way. This tool provides automatic and semi-automatic daily recommendations on the geohazard safety risks based on predictions supported by weather data and hindcasting/forecasting. This tool enables PNG to make field-level risk-based decisions about short-term fieldwork planning and execution to ensure the safe completion of the associated field activities. This article will present PNG and BGC’s challenges and successes in developing and implementing this pioneer solution for managing identified geohazard risks to personnel safety during the fieldwork season. The intent of this paper is to ensure other operators are aware of the available options to manage personnel safety for working in high-risk geohazard terrains.
Li, Ivy; Engelbrecht, Jeanine
Multi-Sensor Remote Sensing Integrated With Mixed Reality To Support Hazard And Risk Communication Conference
44th Canadian Symposium on Remote Sensing, 2023.
@conference{Conference1,
title = {Multi-Sensor Remote Sensing Integrated With Mixed Reality To Support Hazard And Risk Communication},
author = {Ivy Li and Jeanine Engelbrecht},
year = {2023},
date = {2023-06-09},
urldate = {2023-06-09},
booktitle = {44th Canadian Symposium on Remote Sensing},
abstract = {On 13 June 2022, unprecedented amounts of rainfall caused a 500-year flood event within Yellowstone National Park (YNP), resulting in significant flooding, rockslides, and debris flows. Extreme water levels destroyed the access road between Gardiner, Montana, and the Mammoth Hot Springs in Wyoming, and three sections of the Northeast Entrance Road between Lamar Valley and Cooke City/Silver Gate, Montana. Water and wastewater systems, powerlines and other critical park infrastructure were also affected. The North Entrance at Gardiner, through the YNP to Cooke City, is generally the only vehicle access in and out of the YNP during winter with most park roads closing to regular vehicles from early November to late-April (National Park Service 2022). Therefore, rapid recovery and restoration of road access were a priority with a multi-agency response team appointed to execute repairs needed to restore the roads before winter. To support resiliency planning objectives for new infrastructure, the response teams used remote sensing data to inventory active landslides along the transportation corridor to determine suitable options for alternative vehicle access alignments. Site reconnaissance, geologic mapping, lidar change detection, interferometric synthetic aperture radar (InSAR) analysis, and drilling and borehole logging were completed to help understand site geology. The InSAR and lidar change detection results confirmed the presence of several slow-moving landslides (Cruden & Varnes 1996), exhibiting movement rates of up to 30 mm/yr, near the North Entrance corridor. The resulting data was used to develop a hazard map, ranking landslides from most- to least hazardous based on activity and proximity to road infrastructure. The information was targeted towards the assessment of sustainable long-term solutions to restore park access. Due to diverse backgrounds and expertise of response teams including design engineers (working on mitigation design), environmental professionals (involved with resource protection), management, regulatory interests, and community stakeholders, communicating engineering and earth science information among the team in an efficient way was challenging.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
On 13 June 2022, unprecedented amounts of rainfall caused a 500-year flood event within Yellowstone National Park (YNP), resulting in significant flooding, rockslides, and debris flows. Extreme water levels destroyed the access road between Gardiner, Montana, and the Mammoth Hot Springs in Wyoming, and three sections of the Northeast Entrance Road between Lamar Valley and Cooke City/Silver Gate, Montana. Water and wastewater systems, powerlines and other critical park infrastructure were also affected. The North Entrance at Gardiner, through the YNP to Cooke City, is generally the only vehicle access in and out of the YNP during winter with most park roads closing to regular vehicles from early November to late-April (National Park Service 2022). Therefore, rapid recovery and restoration of road access were a priority with a multi-agency response team appointed to execute repairs needed to restore the roads before winter. To support resiliency planning objectives for new infrastructure, the response teams used remote sensing data to inventory active landslides along the transportation corridor to determine suitable options for alternative vehicle access alignments. Site reconnaissance, geologic mapping, lidar change detection, interferometric synthetic aperture radar (InSAR) analysis, and drilling and borehole logging were completed to help understand site geology. The InSAR and lidar change detection results confirmed the presence of several slow-moving landslides (Cruden & Varnes 1996), exhibiting movement rates of up to 30 mm/yr, near the North Entrance corridor. The resulting data was used to develop a hazard map, ranking landslides from most- to least hazardous based on activity and proximity to road infrastructure. The information was targeted towards the assessment of sustainable long-term solutions to restore park access. Due to diverse backgrounds and expertise of response teams including design engineers (working on mitigation design), environmental professionals (involved with resource protection), management, regulatory interests, and community stakeholders, communicating engineering and earth science information among the team in an efficient way was challenging.
Rabczak, Victoria; McClymont, Alastair; Hoppe, William; Alexa, Zachary; Shih, Evan
Near Surface Geophysical Investigation for Geotechnical Geohazard Assessment Using Seismic Refraction and Resistivity Survey Conference
GeoConvention, 2023.
@conference{Conference1,
title = { Near Surface Geophysical Investigation for Geotechnical Geohazard Assessment Using Seismic Refraction and Resistivity Survey},
author = {Victoria Rabczak and Alastair McClymont and William Hoppe and Zachary Alexa and Evan Shih},
year = {2023},
date = {2023-06-06},
urldate = {2023-06-06},
booktitle = {GeoConvention},
abstract = {Uncertainties in geology can cause challenges in geotechnical engineering projects, especially when it comes to applications involving the transport of needed natural resources. Near surface geophysics has been successfully applied in many geotechnical engineering and hazard assessment applications to support borehole and other geologic findings. In this study, seismic refraction tomography (SRT), electrical resistivity tomography (ERT), with supporting claims from multichannel analysis of surface waves (MASW) and borehole logs, were used in a geotechnical engineering application to complete a geohazard assessment at a site located adjacent to a river in the mountains of northern British Columbia. Site geology consisted of cobbles and boulders in an area where a previous debris flow occurred, indicating that hazards associated with the adjacent slopes also need to be considered. The river is regularly imaged using satellite imagery to monitor the river’s migration, which may affect linear infrastructure along the river’s margins. At the site of interest, transmission towers and natural gas pipelines run parallel to a river, seen in Figure 1, where the riverbanks are susceptible to erosion due to the high velocity of the river. The client tasked BGC Engineering (BGC) with answering questions such as; will future bank migration impact the existing infrastructure and to determine ground conditions along a newly proposed alignment, upslope of the existing right of way. With the use of the conducted surveys and provided borehole data, a hazard assessment was successfully completed to aid site planners mitigate the multiple hazards in the area.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Uncertainties in geology can cause challenges in geotechnical engineering projects, especially when it comes to applications involving the transport of needed natural resources. Near surface geophysics has been successfully applied in many geotechnical engineering and hazard assessment applications to support borehole and other geologic findings. In this study, seismic refraction tomography (SRT), electrical resistivity tomography (ERT), with supporting claims from multichannel analysis of surface waves (MASW) and borehole logs, were used in a geotechnical engineering application to complete a geohazard assessment at a site located adjacent to a river in the mountains of northern British Columbia. Site geology consisted of cobbles and boulders in an area where a previous debris flow occurred, indicating that hazards associated with the adjacent slopes also need to be considered. The river is regularly imaged using satellite imagery to monitor the river’s migration, which may affect linear infrastructure along the river’s margins. At the site of interest, transmission towers and natural gas pipelines run parallel to a river, seen in Figure 1, where the riverbanks are susceptible to erosion due to the high velocity of the river. The client tasked BGC Engineering (BGC) with answering questions such as; will future bank migration impact the existing infrastructure and to determine ground conditions along a newly proposed alignment, upslope of the existing right of way. With the use of the conducted surveys and provided borehole data, a hazard assessment was successfully completed to aid site planners mitigate the multiple hazards in the area.
Jones, Daniel; McWatters, Rebecca; Rowe, Kerry; Kalinovich, Indra; Rutter, Alison
PCB Containment Using Geosynthetics in Canada's Arctic Journal Article
In: Polar Science, vol. 36, pp. 100928, 2023.
@article{journal1_53,
title = {PCB Containment Using Geosynthetics in Canada's Arctic},
author = {Daniel Jones and Rebecca McWatters and Kerry Rowe and Indra Kalinovich and Alison Rutter},
doi = {10.1016/j.polar.2023.100928},
year = {2023},
date = {2023-04-28},
urldate = {2023-04-27},
journal = {Polar Science},
volume = {36},
pages = {100928},
abstract = {Two funnel-and-gate permeable reactive barriers (PRBs) with settling ponds comprised of a composite liner (geomembrane and geosynthetic clay liners (GCL)) were installed at Resolution Island (BAF-5), Nunavut to contain residual polychlorinated biphenyls (PCBs) moving with the sediment and annual snowmelt. The long-term performance of the geosynthetics used in the PRB funnels is studied for physical integrity and diffusive barrier properties after nine years of operation. Exhumed geomembrane specimens are compared with virgin material by index testing: diffusive resistance to benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds, as well as puncture, burst, and tensile strength. Exhumed GCLs are evaluated concerning hydraulic conductivity, the mass of bentonite per unit area, and swell index. The migration of PCBs through the composite liner system by diffusion is modelled and the diffusive and sorptive properties of the geomembrane (Dg = 1.7 × 10−14 m2/s, Sgf = 160,000) and GCL (De = 3.1 × 10−10 m2/s, bentonite plus fibers layer Kd = 15 mL/g, cover geotextile Kd = 12,000 mL/g, and carrier geotextile Kd = 16,000 mL/g) were calculated. Modelling results estimate that the composite liner was successfully containing PCBs. This was confirmed by downgradient monitoring. The challenges of the location and terrain, PRB design, construction, and maintenance are discussed along with recommendations for designing PRBs in other remote and cold region environments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Two funnel-and-gate permeable reactive barriers (PRBs) with settling ponds comprised of a composite liner (geomembrane and geosynthetic clay liners (GCL)) were installed at Resolution Island (BAF-5), Nunavut to contain residual polychlorinated biphenyls (PCBs) moving with the sediment and annual snowmelt. The long-term performance of the geosynthetics used in the PRB funnels is studied for physical integrity and diffusive barrier properties after nine years of operation. Exhumed geomembrane specimens are compared with virgin material by index testing: diffusive resistance to benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds, as well as puncture, burst, and tensile strength. Exhumed GCLs are evaluated concerning hydraulic conductivity, the mass of bentonite per unit area, and swell index. The migration of PCBs through the composite liner system by diffusion is modelled and the diffusive and sorptive properties of the geomembrane (Dg = 1.7 × 10−14 m2/s, Sgf = 160,000) and GCL (De = 3.1 × 10−10 m2/s, bentonite plus fibers layer Kd = 15 mL/g, cover geotextile Kd = 12,000 mL/g, and carrier geotextile Kd = 16,000 mL/g) were calculated. Modelling results estimate that the composite liner was successfully containing PCBs. This was confirmed by downgradient monitoring. The challenges of the location and terrain, PRB design, construction, and maintenance are discussed along with recommendations for designing PRBs in other remote and cold region environments.
KC, Rajan; Sharma, Keshab; Burnwal, Monu; Chowdhury, Prishati; Acharya, Indra; Misra, Jibendra
Performance evaluation of Composite Caisson-Pile Foundation (CCPF) in sand using finite element model Conference
Smart Geotechnics for Smart Societies, 2023.
@conference{Conference1,
title = {Performance evaluation of Composite Caisson-Pile Foundation (CCPF) in sand using finite element model},
author = {Rajan KC and Keshab Sharma and Monu Burnwal and Prishati Chowdhury and Indra Acharya and Jibendra Misra},
year = {2023},
date = {2023-04-27},
urldate = {2023-04-27},
booktitle = {Smart Geotechnics for Smart Societies},
pages = {1290-1294},
abstract = {Caisson (Well) foundation has been widely used in South Asian countries like Nepal, India for construction of bridge piers and abutments. Generally, the caisson is cast in the ground and slowly sunk to the desired depth by gravity. But, due to sinking difficulties, designers are discarding it despite its several advantages. To overcome such a peculiar situation by taking advantage of caisson foundation, a composite caisson-pile foundation (CCPF) has been recently proposed and used to construct a bridge foundation in Nepal. This study aims to investigate the load-settlement behaviour of CCPFs resting on sand subjected to vertical load using three-dimensional finite element analyses. Through other numerical and experimental studies, the accuracy of the finite element analysis was proven to be correct and valid. A detailed parametric study is conducted, which includes the influence of pile length, number of piles and friction angle on the performance of CCPF embedded in sand.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Caisson (Well) foundation has been widely used in South Asian countries like Nepal, India for construction of bridge piers and abutments. Generally, the caisson is cast in the ground and slowly sunk to the desired depth by gravity. But, due to sinking difficulties, designers are discarding it despite its several advantages. To overcome such a peculiar situation by taking advantage of caisson foundation, a composite caisson-pile foundation (CCPF) has been recently proposed and used to construct a bridge foundation in Nepal. This study aims to investigate the load-settlement behaviour of CCPFs resting on sand subjected to vertical load using three-dimensional finite element analyses. Through other numerical and experimental studies, the accuracy of the finite element analysis was proven to be correct and valid. A detailed parametric study is conducted, which includes the influence of pile length, number of piles and friction angle on the performance of CCPF embedded in sand.
Porter, Mike
Predicting Annual Displacement Probability of Slow-Moving Landslides Through Markov Chain and Monte Carlo Simulation Conference
JTC1: Natural Slopes and Landslides, 2023.
@conference{Conference1,
title = {Predicting Annual Displacement Probability of Slow-Moving Landslides Through Markov Chain and Monte Carlo Simulation},
author = {Mike Porter},
year = {2023},
date = {2023-04-26},
urldate = {2023-04-27},
booktitle = {JTC1: Natural Slopes and Landslides},
abstract = {Normally slow-moving landslides are complex, dynamic systems. The potential variability in their velocity has important implications for risk assessment, design, monitoring, and maintenance of infrastructure. Markov Chain models offer a systematic, expert-based approach to predict landslide velocity probability distributions over the design life of existing and proposed infrastructure. In many scenarios, infrastructure condition states can be linked to cumulative and/or annual landslide displacement thresholds. Monte Carlo simulation combined with Markov model outputs can be used to estimate the annual probability of landslide displacement threshold exceedances and infrastructure condition state probabilities. In turn, these can facilitate lifecycle cost modelling and risk cost-benefit analysis of landslide stabilization and other management options.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Normally slow-moving landslides are complex, dynamic systems. The potential variability in their velocity has important implications for risk assessment, design, monitoring, and maintenance of infrastructure. Markov Chain models offer a systematic, expert-based approach to predict landslide velocity probability distributions over the design life of existing and proposed infrastructure. In many scenarios, infrastructure condition states can be linked to cumulative and/or annual landslide displacement thresholds. Monte Carlo simulation combined with Markov model outputs can be used to estimate the annual probability of landslide displacement threshold exceedances and infrastructure condition state probabilities. In turn, these can facilitate lifecycle cost modelling and risk cost-benefit analysis of landslide stabilization and other management options.
Subedi, Mandip; KC, Rajan; Acharya, Indra; Sharma, Keshab
Probabilistic Liquefaction Potential of Kathmandu Valley Soil Based on Standard Penetration Tests Journal Article
In: Geoenvironmental Disasters, 2023.
@article{journal1,
title = {Probabilistic Liquefaction Potential of Kathmandu Valley Soil Based on Standard Penetration Tests},
author = {Mandip Subedi and Rajan KC and Indra Acharya and Keshab Sharma},
year = {2023},
date = {2023-04-25},
urldate = {2023-04-27},
journal = {Geoenvironmental Disasters},
abstract = {Despite being a liquefaction susceptible zone, Kathmandu Valley soil in Nepal has limited studies on liquefaction potential and most of them are based on the deterministic approach. Although this method is widely used, it ignores the uncertainties of seismic parameters such as peak ground acceleration, amax, and earthquake magnitude, Mw as well as the inherent variabilities of soil layers, in-situ testing procedures, and geotechnical properties. On the other hand, the probabilistic approach helps assess the liquefaction potential by considering all these uncertainties. In this study, we assess the liquefaction hazard in the Kathmandu Valley using the first-order second-moment (FOSM) method as a probabilistic approach for liquefaction hazard assessment. The assessment is done for three likely-to-recur scenario earthquakes utilizing the geotechnical data of 1510 boreholes. The soils are characterized geotechnically to further assess susceptibility criteria of liquefaction in the valley. The assessment reveals that the central part of the valley is more vulnerable to liquefaction than other parts and the liquefaction probability increases with increasing depth up to 9 m, after which has geared down the value. Moreover, a relationship between the probability of liquefaction (PL) and the factor of safety (FS) against liquefaction is established. The hazard maps prepared for different earthquake scenarios can be useful for future infrastructure planning in Kathmandu Valley.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Despite being a liquefaction susceptible zone, Kathmandu Valley soil in Nepal has limited studies on liquefaction potential and most of them are based on the deterministic approach. Although this method is widely used, it ignores the uncertainties of seismic parameters such as peak ground acceleration, amax, and earthquake magnitude, Mw as well as the inherent variabilities of soil layers, in-situ testing procedures, and geotechnical properties. On the other hand, the probabilistic approach helps assess the liquefaction potential by considering all these uncertainties. In this study, we assess the liquefaction hazard in the Kathmandu Valley using the first-order second-moment (FOSM) method as a probabilistic approach for liquefaction hazard assessment. The assessment is done for three likely-to-recur scenario earthquakes utilizing the geotechnical data of 1510 boreholes. The soils are characterized geotechnically to further assess susceptibility criteria of liquefaction in the valley. The assessment reveals that the central part of the valley is more vulnerable to liquefaction than other parts and the liquefaction probability increases with increasing depth up to 9 m, after which has geared down the value. Moreover, a relationship between the probability of liquefaction (PL) and the factor of safety (FS) against liquefaction is established. The hazard maps prepared for different earthquake scenarios can be useful for future infrastructure planning in Kathmandu Valley.
Lewkowicz, Antoni; Wolfe, Stephen; Rudy, Ashley; Roy-Léveillée, Pascale; Roujanski, Vladislav; O'Neill, Brendan; Koenig, Cassandra; Hoeve, Ed; Gruber, Stephan; Brown, Nick; Brooks, Heather; Bonnaventure, Philip
6th European Conference on Permafrost (EUCOP 6), 2023.
@conference{Conference1,
title = {Progress in the Development of an Illustrated Plain-Language Version of the Glossary of Permafrost and Related Ground-Ice Terms},
author = {Antoni Lewkowicz and Stephen Wolfe and Ashley Rudy and Pascale Roy-Léveillée and Vladislav Roujanski and Brendan O'Neill and Cassandra Koenig and Ed Hoeve and Stephan Gruber and Nick Brown and Heather Brooks and Philip Bonnaventure },
doi = {0.52381/EUCOP6.abstracts.1},
year = {2023},
date = {2023-04-25},
urldate = {2023-04-27},
booktitle = {6th European Conference on Permafrost (EUCOP 6)},
abstract = {The 12 members of the Permafrost Terminology Action Group (PTAG) of the Canadian Permafrost Association have been working since 2021 to update the Glossary of Permafrost and Related Ground-Ice Terms, first published in 1988, and subsequently updated as the IPA’s Multilanguage Glossary. PTAG members have reviewed the 400 terms in the existing Glossary as well as about 100 potential new entries and are currently drafting or editing individual definitions and comments for subsequent approval by the group as a whole. More than 100 of the terms are being considered for inclusion in an illustrated plain-language version of the Glossary which is being drafted simultaneously. This version is aimed at education and outreach, with audiences such as northern residents, the media and non-specialists. The goal is to support clear communication about permafrost and permafrost change through the provision of clear definitions in accessible language. The list of entries includes fundamental terms such as permafrost, ground ice, frost heave, thermokarst, thermosyphon and rock glacier. It also includes certain terms that will appear in the full Glossary for the first time, such as air-cooled embankment, ice cellar, lithalsa, permafrost carbon-climate feedback and yedoma. The text used for entries in the plain-language version generally differs from the technical version, and frequently includes additional information under the heading “Did you know?”, as well as an illustration (photo or diagram). PTAG aims to complete a draft of the illustrated plain-language version and the technical version for feedback in 2023, with publication in time for the 2024 ICOP in Whitehorse.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The 12 members of the Permafrost Terminology Action Group (PTAG) of the Canadian Permafrost Association have been working since 2021 to update the Glossary of Permafrost and Related Ground-Ice Terms, first published in 1988, and subsequently updated as the IPA’s Multilanguage Glossary. PTAG members have reviewed the 400 terms in the existing Glossary as well as about 100 potential new entries and are currently drafting or editing individual definitions and comments for subsequent approval by the group as a whole. More than 100 of the terms are being considered for inclusion in an illustrated plain-language version of the Glossary which is being drafted simultaneously. This version is aimed at education and outreach, with audiences such as northern residents, the media and non-specialists. The goal is to support clear communication about permafrost and permafrost change through the provision of clear definitions in accessible language. The list of entries includes fundamental terms such as permafrost, ground ice, frost heave, thermokarst, thermosyphon and rock glacier. It also includes certain terms that will appear in the full Glossary for the first time, such as air-cooled embankment, ice cellar, lithalsa, permafrost carbon-climate feedback and yedoma. The text used for entries in the plain-language version generally differs from the technical version, and frequently includes additional information under the heading “Did you know?”, as well as an illustration (photo or diagram). PTAG aims to complete a draft of the illustrated plain-language version and the technical version for feedback in 2023, with publication in time for the 2024 ICOP in Whitehorse.
Strouth, Alex; Zubrycky, Sophia; McDougall, Scott
Quantifying Debris-Flow Hazard and Risk Based on Fan Sector Conference
8th International conference on debris flow hazard mitigation, 2023.
@conference{Conference1,
title = {Quantifying Debris-Flow Hazard and Risk Based on Fan Sector},
author = {Alex Strouth and Sophia Zubrycky and Scott McDougall},
year = {2023},
date = {2023-04-18},
urldate = {2023-04-18},
booktitle = {8th International conference on debris flow hazard mitigation},
abstract = {We show how a quantitative estimate of debris-flow hazard and risk can be derived simply from the position of infrastructure on the fan relative to the fan apex and the most likely flow path (e.g., active channel). Fan sectors and the spatial probability of impact in each sector are based on a fan-normalized heat map of debris-flow impacts derived from 146 mapped impact areas across 30 fans in southwestern British Columbia, Canada. As a proof-of-concept, we provide an example for annual life loss risk to an individual who occupies a home in various sectors of a debris-flow fan. The results are comparable to broad findings from quantitative risk assessments completed at 10 fans in British Columbia and Alberta, Canada with similar characteristics. The method presented here is a way to obtain a high-level quantitative risk estimate prior to a detailed site-specific assessment.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
We show how a quantitative estimate of debris-flow hazard and risk can be derived simply from the position of infrastructure on the fan relative to the fan apex and the most likely flow path (e.g., active channel). Fan sectors and the spatial probability of impact in each sector are based on a fan-normalized heat map of debris-flow impacts derived from 146 mapped impact areas across 30 fans in southwestern British Columbia, Canada. As a proof-of-concept, we provide an example for annual life loss risk to an individual who occupies a home in various sectors of a debris-flow fan. The results are comparable to broad findings from quantitative risk assessments completed at 10 fans in British Columbia and Alberta, Canada with similar characteristics. The method presented here is a way to obtain a high-level quantitative risk estimate prior to a detailed site-specific assessment.
Harrington, Jordan; Koenig, Cassandra; Edmunds, Alan; Arenson, Lukas; Wainstein, Pablo
Rock Glacier Cryo-Hydrology in the Central Andes Conference
6th European Conference on Permafrost (EUCOP 6), 2023.
@conference{Conference1,
title = {Rock Glacier Cryo-Hydrology in the Central Andes},
author = {Jordan Harrington and Cassandra Koenig and Alan Edmunds and Lukas Arenson and Pablo Wainstein},
doi = {0.52381/EUCOP6.abstracts.1},
year = {2023},
date = {2023-04-02},
urldate = {2023-04-01},
booktitle = {6th European Conference on Permafrost (EUCOP 6)},
abstract = {Many semi-arid areas downstream of mountain ranges around the world are experiencing water stress and uncertainty in future water availability due to changing water use and shifting hydrological regimes. Some of these cold, dry mountain headwaters contain rock glaciers, which can store water in the form of permafrost ground ice. Various studies have reported on the distribution of rock glaciers and have attempted to constrain ranges of water volume stored as ground ice. However, the understanding of rock glacier hydrological processes and functions in watershed hydrology remains limited by the relative scarcity of subsurface geological, thermal, and hydrological data in these or other periglacial landforms. Towards addressing these gaps, we present a case study from the Central Andes of South America with some of the relatively few instrumented boreholes in rock glaciers worldwide, complemented with geophysical surveys. Up to six years of monitoring data were used to develop conceptual thermal and hydrological models. Numerical thermal models were used to evaluate permafrost thaw and the potential contribution of associated ground ice melt to streamflow. Key findings to date are: i) stratigraphy and ground ice content were heterogeneous within individual rock glaciers and also compared to other rock glaciers within the same watershed; ii) water flow can occur yearround in rock glaciers via supra-permafrost taliks and sub-permafrost fractured rock and/or basal sediments; and iii) modelled permafrost thaw was relatively slow, and, when considered at either the sub-watershed or watershed scale, associated ground ice melt was a minor contributor to the water budget.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Many semi-arid areas downstream of mountain ranges around the world are experiencing water stress and uncertainty in future water availability due to changing water use and shifting hydrological regimes. Some of these cold, dry mountain headwaters contain rock glaciers, which can store water in the form of permafrost ground ice. Various studies have reported on the distribution of rock glaciers and have attempted to constrain ranges of water volume stored as ground ice. However, the understanding of rock glacier hydrological processes and functions in watershed hydrology remains limited by the relative scarcity of subsurface geological, thermal, and hydrological data in these or other periglacial landforms. Towards addressing these gaps, we present a case study from the Central Andes of South America with some of the relatively few instrumented boreholes in rock glaciers worldwide, complemented with geophysical surveys. Up to six years of monitoring data were used to develop conceptual thermal and hydrological models. Numerical thermal models were used to evaluate permafrost thaw and the potential contribution of associated ground ice melt to streamflow. Key findings to date are: i) stratigraphy and ground ice content were heterogeneous within individual rock glaciers and also compared to other rock glaciers within the same watershed; ii) water flow can occur yearround in rock glaciers via supra-permafrost taliks and sub-permafrost fractured rock and/or basal sediments; and iii) modelled permafrost thaw was relatively slow, and, when considered at either the sub-watershed or watershed scale, associated ground ice melt was a minor contributor to the water budget.
Hu, Yan; Arenson, Lukas; Barboux, Chloe; Bodin, Xavier; Cicoira, Alessandro; Delaloye, Reynald; Gartner-Roer, Isabelle; Kaab, Andreas; Kellerer-Pirklbauer, Andreas; Lambiel, Christophe; Liu, Lin; Pellet, Cecile; Rouyet, Line; Schoeneich, Philippe; Seier, Gernot; Strozzi, Tazio
Rock Glacier Velocity as a New Product of the Essential Climate Variable Permafrost Conference
6th European Conference on Permafrost (EUCOP 6), 2023.
@conference{Conference1_168,
title = {Rock Glacier Velocity as a New Product of the Essential Climate Variable Permafrost},
author = {Yan Hu and Lukas Arenson and Chloe Barboux and Xavier Bodin and Alessandro Cicoira and Reynald Delaloye and Isabelle Gartner-Roer and Andreas Kaab and Andreas Kellerer-Pirklbauer and Christophe Lambiel and Lin Liu and Cecile Pellet and Line Rouyet and Philippe Schoeneich and Gernot Seier and Tazio Strozzi},
doi = {0.52381/EUCOP6.abstracts.1},
year = {2023},
date = {2023-04-01},
booktitle = {6th European Conference on Permafrost (EUCOP 6)},
abstract = {“Rock Glacier Velocity (RGV)” was recently accepted by the Global Climate Observing System as a new product of the Essential Climate Variable Permafrost. Our contribution synthesizes knowledge on rock glacier kinematics (general mechanical behavior) and velocities (quantifiable variable) to assess the scientific relevance of RGV. We aim to gain perspectives on the global and regional patterns of rock glacier velocities across temporal scales as revealed by observations. We conducted the systematic review with reference to the PRISMA 2020 Statement to facilitate a transparent review. Among the 105 core articles from the period 1919–2022 reviewed in this work, we found that: (1) existing studies have a near-global, yet uneven, regional coverage as the majority of the papers (54 %) describe rock glaciers in Central and Southern Europe; (2) with a rapid increase in the number of publications during recent decades, most of the studies were published since the 1990s (90 %); and (3) Spaceborne/Airborne/UAV-borne remote sensing is the most frequently employed approach (45 %) for measuring rock glacier velocities followed by close-range remote sensing (40%) and in-situ (15 %) techniques. At a global scale, rock glacier kinematics is primarily characterized by a (multi-) decennial acceleration trend with regional variabilities in terms of onset timing and magnitude. This long-term pattern is found on rock glaciers in areas where observations are available, especially since the 2000s, such as the European Alps, High Mountain Asia, the Rocky Mountains, the Andes, and Scandinavia. A pronounced seasonal rhythm – velocities commonly reach the maxima between late summer to early winter and minima in late spring – occurs on many, yet not all, monitored rock glaciers. With the increasing availability of continuous observations during the past two decades, a synchronous kinematic pattern at the inter-annual scale is identified in the European Alps at the regional scale despite apparent differences in local topo-climatic conditions.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
“Rock Glacier Velocity (RGV)” was recently accepted by the Global Climate Observing System as a new product of the Essential Climate Variable Permafrost. Our contribution synthesizes knowledge on rock glacier kinematics (general mechanical behavior) and velocities (quantifiable variable) to assess the scientific relevance of RGV. We aim to gain perspectives on the global and regional patterns of rock glacier velocities across temporal scales as revealed by observations. We conducted the systematic review with reference to the PRISMA 2020 Statement to facilitate a transparent review. Among the 105 core articles from the period 1919–2022 reviewed in this work, we found that: (1) existing studies have a near-global, yet uneven, regional coverage as the majority of the papers (54 %) describe rock glaciers in Central and Southern Europe; (2) with a rapid increase in the number of publications during recent decades, most of the studies were published since the 1990s (90 %); and (3) Spaceborne/Airborne/UAV-borne remote sensing is the most frequently employed approach (45 %) for measuring rock glacier velocities followed by close-range remote sensing (40%) and in-situ (15 %) techniques. At a global scale, rock glacier kinematics is primarily characterized by a (multi-) decennial acceleration trend with regional variabilities in terms of onset timing and magnitude. This long-term pattern is found on rock glaciers in areas where observations are available, especially since the 2000s, such as the European Alps, High Mountain Asia, the Rocky Mountains, the Andes, and Scandinavia. A pronounced seasonal rhythm – velocities commonly reach the maxima between late summer to early winter and minima in late spring – occurs on many, yet not all, monitored rock glaciers. With the increasing availability of continuous observations during the past two decades, a synchronous kinematic pattern at the inter-annual scale is identified in the European Alps at the regional scale despite apparent differences in local topo-climatic conditions.
Acharya, Prabin; Sharma, Keshab; Acharya, Indra; Adhikari, Rachana
Seismic Liquefaction Potential of Fluvio-Lacustrine Deposit in the Kathmandu Valley, Nepal Journal Article
In: Geotechnical and Geological Engineering, vol. 41, no. 3, pp. 1977-1997, 2023.
@article{journal1,
title = {Seismic Liquefaction Potential of Fluvio-Lacustrine Deposit in the Kathmandu Valley, Nepal},
author = {Prabin Acharya and Keshab Sharma and Indra Acharya and Rachana Adhikari},
doi = {10.1007/s10706-023-02387-8},
year = {2023},
date = {2023-03-30},
urldate = {2023-03-18},
journal = {Geotechnical and Geological Engineering},
volume = {41},
number = {3},
pages = {1977-1997},
abstract = {Valleys containing Fluvial-lacustrine deposits with shallow groundwater are susceptible to seismic liquefaction. In fact, extensive liquefaction was observed in the Kathmandu Valley during earlier earthquakes. The factor of safety and liquefaction potential index (LPI) were calculated using the simplified procedure of liquefaction potential assessment for 143 standard penetration test (SPT) profiles, conducted in different surface geological units of the valley, based upon which, a liquefaction susceptibility map for Kathmandu Valley has been proposed. The result shows that 44.4% of the area in Kathmandu valley lies in very high risk, 28.36% in high risk, 21.53% in low risk, and 5.71% in very low risk of liquefaction hazard.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Valleys containing Fluvial-lacustrine deposits with shallow groundwater are susceptible to seismic liquefaction. In fact, extensive liquefaction was observed in the Kathmandu Valley during earlier earthquakes. The factor of safety and liquefaction potential index (LPI) were calculated using the simplified procedure of liquefaction potential assessment for 143 standard penetration test (SPT) profiles, conducted in different surface geological units of the valley, based upon which, a liquefaction susceptibility map for Kathmandu Valley has been proposed. The result shows that 44.4% of the area in Kathmandu valley lies in very high risk, 28.36% in high risk, 21.53% in low risk, and 5.71% in very low risk of liquefaction hazard.
Horita, Kathleen
Simulating Two-Phase Debris Flows in HEC-RAS at Hummingbird Creek, British Columbia, Canada Conference
8th International Conference on Debris Flow Hazard Mitigation, 2023.
@conference{Conference1,
title = {Simulating Two-Phase Debris Flows in HEC-RAS at Hummingbird Creek, British Columbia, Canada},
author = {Kathleen Horita},
year = {2023},
date = {2023-03-29},
urldate = {2023-03-18},
booktitle = {8th International Conference on Debris Flow Hazard Mitigation},
abstract = {Debris flows are typically modelled as a single homogeneous surge due to lack of data to support more complex model development and due to lack of time and funding for the practitioner and the communities they aim to support. Coarse debris flows are frequently characterized by a coarse front, followed by a muddy slurry, that is then followed by a hyperconcentrated flow phase with lesser sediment concentrations. Presented herein is the modelling for a debris flow hazard assessment for Hummingbird Creek, British Columbia, Canada. Model calibration best matched the observed debris flow deposit when the coarse front and hyperconcentrated flow were modelled separately in two phases allowing for separate flow rheologies to be used for the front and the tail of the debris flow, and allowing for deposition between phases. Further research is needed to understand when simulation of two-phase flow may be most representative, particularly when no calibration data is available.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Debris flows are typically modelled as a single homogeneous surge due to lack of data to support more complex model development and due to lack of time and funding for the practitioner and the communities they aim to support. Coarse debris flows are frequently characterized by a coarse front, followed by a muddy slurry, that is then followed by a hyperconcentrated flow phase with lesser sediment concentrations. Presented herein is the modelling for a debris flow hazard assessment for Hummingbird Creek, British Columbia, Canada. Model calibration best matched the observed debris flow deposit when the coarse front and hyperconcentrated flow were modelled separately in two phases allowing for separate flow rheologies to be used for the front and the tail of the debris flow, and allowing for deposition between phases. Further research is needed to understand when simulation of two-phase flow may be most representative, particularly when no calibration data is available.
Fraunenfelder, Regula; Lato, Matthew; Biskupic, Marek
Snow Avalanche Detection and Mapping by Satellite Remote Sensing Conference
Global Space Conference on Climate Change, 2023.
@conference{Conference1g,
title = {Snow Avalanche Detection and Mapping by Satellite Remote Sensing},
author = {Regula Fraunenfelder and Matthew Lato and Marek Biskupic},
year = {2023},
date = {2023-03-28},
urldate = {2023-03-18},
booktitle = {Global Space Conference on Climate Change},
abstract = {World-wide, snow avalanches are one of the main natural hazard in cold-climate mountain regions, leading to the interruption of transport lines and supply chains, and threatening life and infrastructure. In many countries, the regions requiring avalanche forecasting are vast and the assessment of the snow avalanche situation over areas of several thousand square kilometres an enormous task. For a snow avalanche expert, it takes several hours to visually inspect and map individual snow avalanche paths. At times this task cannot be accomplished before several days after a snow avalanche cycle. Several studies have shown that data from space-borne optical sensors, as well as from radar sensors, can be used to detect and map snow avalanche debris. The good spatial resolution, the large spatial coverage, and the reliable, regular data acquisition provided by recent satellites (both optical and SAR) is seen as a much-needed and valuable new source of information for tasks related to avalanche hazards assessment and forecasting. Being able to remotely detect and record snow avalanches aids to target mitigation strategies. Here we present several examples on how the analysis of optical and radar satellite data can yield hind-cast snow avalanche inventory observations on a regional scale. Automatic snow avalanche mapping in very high resolution optical imagery is seen as most applicable to update avalanche data bases, e.g. after large avalanche cycles. In contrast, for more near real-time and real-time oriented applications, such as snow avalanche danger forecasting, the use of SAR data is seen as most feasible, among others due to the independency of clear sky and illumination conditions of SAR sensors and the free access to data with sufficient resolution and high temporal area coverage.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
World-wide, snow avalanches are one of the main natural hazard in cold-climate mountain regions, leading to the interruption of transport lines and supply chains, and threatening life and infrastructure. In many countries, the regions requiring avalanche forecasting are vast and the assessment of the snow avalanche situation over areas of several thousand square kilometres an enormous task. For a snow avalanche expert, it takes several hours to visually inspect and map individual snow avalanche paths. At times this task cannot be accomplished before several days after a snow avalanche cycle. Several studies have shown that data from space-borne optical sensors, as well as from radar sensors, can be used to detect and map snow avalanche debris. The good spatial resolution, the large spatial coverage, and the reliable, regular data acquisition provided by recent satellites (both optical and SAR) is seen as a much-needed and valuable new source of information for tasks related to avalanche hazards assessment and forecasting. Being able to remotely detect and record snow avalanches aids to target mitigation strategies. Here we present several examples on how the analysis of optical and radar satellite data can yield hind-cast snow avalanche inventory observations on a regional scale. Automatic snow avalanche mapping in very high resolution optical imagery is seen as most applicable to update avalanche data bases, e.g. after large avalanche cycles. In contrast, for more near real-time and real-time oriented applications, such as snow avalanche danger forecasting, the use of SAR data is seen as most feasible, among others due to the independency of clear sky and illumination conditions of SAR sensors and the free access to data with sufficient resolution and high temporal area coverage.
KC, Rajan; Sharma, Keshab; Chowdhury, Prishati; Burnwal, Monu; Misra, Jibendra
State-of-the-Art Review of Composite Caisson-Pile Foundation (CCPF) Journal Article
In: Applied Ocean Research, vol. 136, no. 103571, 2023.
@article{journal1,
title = { State-of-the-Art Review of Composite Caisson-Pile Foundation (CCPF)},
author = {Rajan KC and Keshab Sharma and Prishati Chowdhury and Monu Burnwal and Jibendra Misra},
doi = {/10.1016/j.apor.2023.103571},
year = {2023},
date = {2023-03-27},
urldate = {2023-03-18},
journal = {Applied Ocean Research},
volume = {136},
number = {103571},
abstract = {Caissons and piles are two primary foundation types for deep-water bridges. Caissons are suitable for long-span bridges, deep alluvial deposits, liquefiable soils, and sufficient vessel collisions, but can be problematic due to sinking issues and inadequate earthquake resistance. Pile foundations are not suitable for deep water because of their extensive length, reduced rigidity, low vessel collision resistance, and difficulties in construction. A solution to the above problem can be a combination of caisson and piles, known as a Composite Caisson-Pile Foundation (CCPF), which considers the advantages of both foundation types, increasing their strengths without their flaws. After the caisson has reached the required depth, piles may be driven into it to construct a CCPF. Existing caisson foundations can be retrofitted using this approach. However, CCPFs have not been extensively employed due to a lack of thorough study on their geotechnical and structural behavior. This article reviews studies on CCPF systems under various loading condition types (static, cyclic, and dynamic) using different research methodologies (experimental, analytical, and numerical). Overall, this article provides basic insights into CCPFs and the studies related to bridges supported on CCPFs. The outcome of this study can benefit the foundation engineering community and provide a collective idea of this newly developed, innovative foundation system.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Caissons and piles are two primary foundation types for deep-water bridges. Caissons are suitable for long-span bridges, deep alluvial deposits, liquefiable soils, and sufficient vessel collisions, but can be problematic due to sinking issues and inadequate earthquake resistance. Pile foundations are not suitable for deep water because of their extensive length, reduced rigidity, low vessel collision resistance, and difficulties in construction. A solution to the above problem can be a combination of caisson and piles, known as a Composite Caisson-Pile Foundation (CCPF), which considers the advantages of both foundation types, increasing their strengths without their flaws. After the caisson has reached the required depth, piles may be driven into it to construct a CCPF. Existing caisson foundations can be retrofitted using this approach. However, CCPFs have not been extensively employed due to a lack of thorough study on their geotechnical and structural behavior. This article reviews studies on CCPF systems under various loading condition types (static, cyclic, and dynamic) using different research methodologies (experimental, analytical, and numerical). Overall, this article provides basic insights into CCPFs and the studies related to bridges supported on CCPFs. The outcome of this study can benefit the foundation engineering community and provide a collective idea of this newly developed, innovative foundation system.
Subedi, Mandip; Acharya, Indra; Sharma, Keshab; Adhikari, Kalpana; KC, Rajan; Bhandary, Netra
Statistical Analysis Based Geotechnical Characterization of Kathmandu Soils Conference
Smart Geotechnics for Smart Societies, 2023.
@conference{Conference1,
title = {Statistical Analysis Based Geotechnical Characterization of Kathmandu Soils},
author = {Mandip Subedi and Indra Acharya and Keshab Sharma and Kalpana Adhikari and Rajan KC and Netra Bhandary},
url = {https://www.taylorfrancis.com/chapters/oa-edit/10.1201/9781003299127-41/statistical-analysis-based-geotechnical-characterization-kathmandu-soils-mandip-subedi-indra-prasad-acharya-keshab-sharma-kalpana-adhikari-rajan-kc-netra-prakash-bhandary},
year = {2023},
date = {2023-03-26},
urldate = {2023-03-26},
booktitle = {Smart Geotechnics for Smart Societies},
pages = {394-401},
abstract = {Kathmandu Valley, the capital of Nepal, is a highly populated and rapidly urbanised area of the country built upon lacustrine and fluvial origin deposits. Because the valley deposit is located in an earthquake-prone zone with a long history of catastrophic earthquakes, it is vulnerable to numerous geohazards like liquefaction. Although a few localized geotechnical studies have been conducted in the valley, holistic understanding, modelling, and geotechnical soil characterisation are seldom documented. This study attempts to characterize the Kathmandu soil based on geotechnical properties using statistical analysis approach. We have collected and analysed more than 400 geotechnical investigation reports and bored 10 test locations. Statistical analysis and representation of index properties, consolidation parameters, shear strength, SPT-N value, and shear wave velocity have been assessed in this paper. These findings can aid structural and foundation engineers in studying foundations, cost estimation of geotechnical investigations, and planning and implementing various civil engineering projects.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Kathmandu Valley, the capital of Nepal, is a highly populated and rapidly urbanised area of the country built upon lacustrine and fluvial origin deposits. Because the valley deposit is located in an earthquake-prone zone with a long history of catastrophic earthquakes, it is vulnerable to numerous geohazards like liquefaction. Although a few localized geotechnical studies have been conducted in the valley, holistic understanding, modelling, and geotechnical soil characterisation are seldom documented. This study attempts to characterize the Kathmandu soil based on geotechnical properties using statistical analysis approach. We have collected and analysed more than 400 geotechnical investigation reports and bored 10 test locations. Statistical analysis and representation of index properties, consolidation parameters, shear strength, SPT-N value, and shear wave velocity have been assessed in this paper. These findings can aid structural and foundation engineers in studying foundations, cost estimation of geotechnical investigations, and planning and implementing various civil engineering projects.
Weatherly, Hamish
Steep Creek Geohazards and the 2021 Flood Events on the Melamchi River Conference
GeoMandu: Geohazards and Geo-Infra Disasters, 2023.
@conference{Conference1,
title = {Steep Creek Geohazards and the 2021 Flood Events on the Melamchi River},
author = {Hamish Weatherly},
year = {2023},
date = {2023-03-26},
urldate = {2023-03-18},
booktitle = {GeoMandu: Geohazards and Geo-Infra Disasters},
pages = {6-8},
abstract = {Steep creek or hydrogeomorphic hazards are natural hazards that involve a mixture of water ("hydro") and debris or sediment ("geo"). Identifying and assessing hydrogeomorphic hazards is becoming increasingly important as populations increase in mountainous environments and climate change effects (e.g., glacier and permafrost melt exposing unconsolidated sediments, increased rainfall) impact their frequency and magnitude. This presentation provides an overview of steep creek hazards and how to differentiate between the processes based on topographic and geomorphic evidence. A case study of the Melamchi Water Supply Project (MWSP) is then discussed within this framework. The MWSP diverts water from Melamchi River to Kathmandu, Nepal through a 26 km long conveyance tunnel.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Steep creek or hydrogeomorphic hazards are natural hazards that involve a mixture of water ("hydro") and debris or sediment ("geo"). Identifying and assessing hydrogeomorphic hazards is becoming increasingly important as populations increase in mountainous environments and climate change effects (e.g., glacier and permafrost melt exposing unconsolidated sediments, increased rainfall) impact their frequency and magnitude. This presentation provides an overview of steep creek hazards and how to differentiate between the processes based on topographic and geomorphic evidence. A case study of the Melamchi Water Supply Project (MWSP) is then discussed within this framework. The MWSP diverts water from Melamchi River to Kathmandu, Nepal through a 26 km long conveyance tunnel.
Gygax, Adrian; Kostaschuk, Rod; Gaib, Sarah
Structural Aspects of the stabilization of Ten Mile Slide Journal Article
In: Deep Foundations, iss. July / August, pp. 14-20, 2023.
@article{journal1,
title = {Structural Aspects of the stabilization of Ten Mile Slide},
author = {Adrian Gygax and Rod Kostaschuk and Sarah Gaib},
url = {file:///C:/Users/jhobson/Downloads/DEEP-FOUNDATIONS_july-august-2023.pdf},
year = {2023},
date = {2023-03-25},
urldate = {2023-03-28},
journal = {Deep Foundations},
issue = {July / August},
pages = {14-20},
abstract = {A landslide first detected in 1988 along Highway 99 is estimated to have regressed more than 205m (800ft) up slope in the last 40 years, making this section one of the most expensive and challenging for the British Columbia Ministry of Transportation and Infrastructure to maintain. A successful stabilization program significantly reduced operating costs, and its innovative solution, including design and monitoring, is being considered for other landslide sites in the province.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A landslide first detected in 1988 along Highway 99 is estimated to have regressed more than 205m (800ft) up slope in the last 40 years, making this section one of the most expensive and challenging for the British Columbia Ministry of Transportation and Infrastructure to maintain. A successful stabilization program significantly reduced operating costs, and its innovative solution, including design and monitoring, is being considered for other landslide sites in the province.
KC, Rajan; Acharya, Indra; Chowdhury, Prishati; Sharma, Keshab
Study of Behaviour of Composite Caisson-Pile Foundation (CCPF) Based on Experimental and Numerical Analysis Conference
GeoMandu: Geohazards and Geo-Infra Disasters, 2023.
@conference{Conference1,
title = {Study of Behaviour of Composite Caisson-Pile Foundation (CCPF) Based on Experimental and Numerical Analysis},
author = {Rajan KC and Indra Acharya and Prishati Chowdhury and Keshab Sharma},
year = {2023},
date = {2023-03-24},
urldate = {2023-03-29},
booktitle = {GeoMandu: Geohazards and Geo-Infra Disasters},
pages = {91-93},
abstract = {Caisson foundations are commonly used in South Asian countries for constructing bridge piers and abutments. However, sinking challenges have led designers to abandon this foundation type (Abdrabbo and Gaaver, 2012). To address this issue, a composite caisson-pile foundation (CCPF) has been developed, which combines the benefits of both foundation types to enhance their strengths without introducing any weaknesses (Zhang et al., 2019). The CCPF has been used to build bridge foundations in Nepal and has proven effective in difficult site conditions, reducing construction time and costs. The CCPF has not been widely used due to a lack of research on its geotechnical and structural behavior (Zhong and Huang, 2014; Tu et al., 2020). This study reviews pioneering research on CCPF systems, categorizing them by loading type (static, cyclic, and dynamic) and research methodology (experimental, analytical, and numerical) to provide a summary of prior research and the current state of the art. Physical model tests were conducted on instrumented sand-embedded CCPF under static vertical, monotonic lateral, and combined loading to examine load settlement, load improvement ratio (LIR), settlement reduction ratio (SRR), and load-sharing characteristics. A three-dimensional finite element model of CCPF was developed in PLAXIS 3D using experimental data to analyze the impact of significant factors influencing the performance of this foundation during loading.
},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Caisson foundations are commonly used in South Asian countries for constructing bridge piers and abutments. However, sinking challenges have led designers to abandon this foundation type (Abdrabbo and Gaaver, 2012). To address this issue, a composite caisson-pile foundation (CCPF) has been developed, which combines the benefits of both foundation types to enhance their strengths without introducing any weaknesses (Zhang et al., 2019). The CCPF has been used to build bridge foundations in Nepal and has proven effective in difficult site conditions, reducing construction time and costs. The CCPF has not been widely used due to a lack of research on its geotechnical and structural behavior (Zhong and Huang, 2014; Tu et al., 2020). This study reviews pioneering research on CCPF systems, categorizing them by loading type (static, cyclic, and dynamic) and research methodology (experimental, analytical, and numerical) to provide a summary of prior research and the current state of the art. Physical model tests were conducted on instrumented sand-embedded CCPF under static vertical, monotonic lateral, and combined loading to examine load settlement, load improvement ratio (LIR), settlement reduction ratio (SRR), and load-sharing characteristics. A three-dimensional finite element model of CCPF was developed in PLAXIS 3D using experimental data to analyze the impact of significant factors influencing the performance of this foundation during loading.
Park, Jack; Hutchinson, Jean
Systems-Level Geohazard Risk Assessment in Southwestern British Columbia, Canada Conference
EGU General Assembly, 2023.
@conference{Conference1h,
title = {Systems-Level Geohazard Risk Assessment in Southwestern British Columbia, Canada},
author = {Jack Park and Jean Hutchinson},
doi = {10.5194/egusphere-egu23-4277},
year = {2023},
date = {2023-03-23},
urldate = {2023-03-30},
booktitle = {EGU General Assembly},
abstract = {In Western Canada, geohazards can be related to tectonic events, such as earthquakes and volcanoes, but many are weather-driven events, such as floods, landslides, rockfalls, and snow avalanches. Anthropogenic activities, such as residential development, infrastructure, and climate change also contribute to and increase the overall risk from, geohazards. A recent example is the atmospheric river event that devastated much of the southern British Columbia (BC) province in November 2021. Between November 14 and 15, 2021, a 2,500 km long plume of moisture (atmospheric river) hit the west coast of BC and accumulated significant rainfall breaking 20 rainfall records across the province. This intense rainfall event resulted in regional flooding and triggered numerous landslides across the southern province. The impact included closures of all major transportation corridors, severed rail lines, with no rail connections between Kamloops and Vancouver, and evacuation of close to 15,000 residents. In Western Canada, many geohazards risk assessments are performed within the risk management framework outlined by the Canadian Standards Association. Though guidelines exist, such as the Canadian Technical Guidelines on Landslides, there is no national or provincial standard for managing risk associated with geohazards. Furthermore, BC’s Municipalities Act, which allows individual municipality jurisdictions to manage their own risk, results in uneven distribution of funding and almost always results in emergency response. The insured losses from the November 2021 atmospheric river event are estimated to be $500 million CAD ($370 million USD) and uninsured losses are $9 billion CAD ($6.7 billion USD) and counting. These losses do not account for economic losses due to the closure of major transportation infrastructure networks. Immediate efforts following the November 2021 atmospheric river event focused on opening the major highway routes. However, the rebuilding of failed bridge and highway embankments is considered a temporary solution and further upgrades in designs are needed to account for the increasing frequency and magnitude of future atmospheric river events. With limited resources at all levels of government, the risk associated with regional-level geohazard triggers needs to be better understood in order to prioritize road infrastructure capacity. Keeping the critical highway arteries open is important not only for economic benefits but to allow for emergency access for communities. This research looks to help prioritize road infrastructure capacity based on its vulnerability to atmospheric river-triggered geohazard events. Information related to road closures, geohazard events, and infrastructure damages is compiled and related to preconditions of weather trends and infrastructure capacity leading up to the November 2021 event. Road network analysis is performed by defining consequence assessment parameters, such as average daily traffic, associated economic revenue, availability of safety stopping zones, and infrastructure redundancy. Then the risk is assessed based on the vulnerability assignment of different segments of the road network which is presented in a criticality map.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In Western Canada, geohazards can be related to tectonic events, such as earthquakes and volcanoes, but many are weather-driven events, such as floods, landslides, rockfalls, and snow avalanches. Anthropogenic activities, such as residential development, infrastructure, and climate change also contribute to and increase the overall risk from, geohazards. A recent example is the atmospheric river event that devastated much of the southern British Columbia (BC) province in November 2021. Between November 14 and 15, 2021, a 2,500 km long plume of moisture (atmospheric river) hit the west coast of BC and accumulated significant rainfall breaking 20 rainfall records across the province. This intense rainfall event resulted in regional flooding and triggered numerous landslides across the southern province. The impact included closures of all major transportation corridors, severed rail lines, with no rail connections between Kamloops and Vancouver, and evacuation of close to 15,000 residents. In Western Canada, many geohazards risk assessments are performed within the risk management framework outlined by the Canadian Standards Association. Though guidelines exist, such as the Canadian Technical Guidelines on Landslides, there is no national or provincial standard for managing risk associated with geohazards. Furthermore, BC’s Municipalities Act, which allows individual municipality jurisdictions to manage their own risk, results in uneven distribution of funding and almost always results in emergency response. The insured losses from the November 2021 atmospheric river event are estimated to be $500 million CAD ($370 million USD) and uninsured losses are $9 billion CAD ($6.7 billion USD) and counting. These losses do not account for economic losses due to the closure of major transportation infrastructure networks. Immediate efforts following the November 2021 atmospheric river event focused on opening the major highway routes. However, the rebuilding of failed bridge and highway embankments is considered a temporary solution and further upgrades in designs are needed to account for the increasing frequency and magnitude of future atmospheric river events. With limited resources at all levels of government, the risk associated with regional-level geohazard triggers needs to be better understood in order to prioritize road infrastructure capacity. Keeping the critical highway arteries open is important not only for economic benefits but to allow for emergency access for communities. This research looks to help prioritize road infrastructure capacity based on its vulnerability to atmospheric river-triggered geohazard events. Information related to road closures, geohazard events, and infrastructure damages is compiled and related to preconditions of weather trends and infrastructure capacity leading up to the November 2021 event. Road network analysis is performed by defining consequence assessment parameters, such as average daily traffic, associated economic revenue, availability of safety stopping zones, and infrastructure redundancy. Then the risk is assessed based on the vulnerability assignment of different segments of the road network which is presented in a criticality map.
Mark, Emily; Strouth, Alex
The Cheekeye Debris-Flow Barrier - Unique Features of a Proposed Open Check Dam in Canada Conference
8th International conference on debris flow hazard mitigation, 2023.
@conference{Conference1_145,
title = {The Cheekeye Debris-Flow Barrier - Unique Features of a Proposed Open Check Dam in Canada},
author = {Emily Mark and Alex Strouth},
year = {2023},
date = {2023-03-16},
urldate = {2023-03-31},
booktitle = {8th International conference on debris flow hazard mitigation},
abstract = {The proposed Cheekeye debris-flow barrier in Squamish, BC, Canada is an open check dam with a very large storage capacity of 2.4 million m3 . There are several unique features of the design that deviate from standard international practice, including the very low probability (1 in 10,000 years) design event, the use of a single large structure, the selected construction material, the crest design, and the outlet design. These features were selected for the Cheekeye barrier due to idiosyncrasies of the site specifically, and of debris-flow mitigation in Canada, in general.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The proposed Cheekeye debris-flow barrier in Squamish, BC, Canada is an open check dam with a very large storage capacity of 2.4 million m3 . There are several unique features of the design that deviate from standard international practice, including the very low probability (1 in 10,000 years) design event, the use of a single large structure, the selected construction material, the crest design, and the outlet design. These features were selected for the Cheekeye barrier due to idiosyncrasies of the site specifically, and of debris-flow mitigation in Canada, in general.
White, Rachel; Anderson, Sam; Booth, James; Braich, Ginni; Draeger, Christina; Fei, Cuiyi; Harley, Christopher; Handerson, Sarah; Jakob, Matthias; Lau, Carie-Ann; Admasu, Lualawi; Narinesingh, Veeshan; Rodell, Christopher; Roocroft, Eliott; Wingberger, Kate; West, Greg
The Unprecedented Pacific Northwest Heatwave of June 2021 Journal Article
In: Nature Communications, vol. 14, 2023.
@article{journal1f,
title = {The Unprecedented Pacific Northwest Heatwave of June 2021},
author = {Rachel White and Sam Anderson and James Booth and Ginni Braich and Christina Draeger and Cuiyi Fei and Christopher Harley and Sarah Handerson and Matthias Jakob and Carie-Ann Lau and Lualawi Admasu and Veeshan Narinesingh and Christopher Rodell and Eliott Roocroft and Kate Wingberger and Greg West},
doi = {10.1038/s41467-023-36289-3},
year = {2023},
date = {2023-03-15},
urldate = {2023-03-04},
journal = {Nature Communications},
volume = {14},
abstract = {In late June 2021 a heatwave of unprecedented magnitude impacted the Pacific Northwest region of Canada and the United States. Many locations broke all time maximum temperature records by more than 5 °C, and the Canadian national temperature record was broken by 4.6 °C, with a new record temperature of 49.6 °C. Here, we provide a comprehensive summary of this event and its impacts. Upstream diabatic heating played a key role in the magnitude of this anomaly. Weather forecasts provided advanced notice of the event, while sub-seasonal forecasts showed an increased likelihood of a heat extreme with lead times of 10-20 days. The impacts of this event were catastrophic, including hundreds of attributable deaths across the Pacific Northwest, mass-mortalities of marine life, reduced crop and fruit yields, river flooding from rapid snow and glacier melt, and a substantial increase in wildfires—the latter contributing to landslides in the months following. These impacts provide examples we can learn from and a vivid depiction of how climate change can be so devastating.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In late June 2021 a heatwave of unprecedented magnitude impacted the Pacific Northwest region of Canada and the United States. Many locations broke all time maximum temperature records by more than 5 °C, and the Canadian national temperature record was broken by 4.6 °C, with a new record temperature of 49.6 °C. Here, we provide a comprehensive summary of this event and its impacts. Upstream diabatic heating played a key role in the magnitude of this anomaly. Weather forecasts provided advanced notice of the event, while sub-seasonal forecasts showed an increased likelihood of a heat extreme with lead times of 10-20 days. The impacts of this event were catastrophic, including hundreds of attributable deaths across the Pacific Northwest, mass-mortalities of marine life, reduced crop and fruit yields, river flooding from rapid snow and glacier melt, and a substantial increase in wildfires—the latter contributing to landslides in the months following. These impacts provide examples we can learn from and a vivid depiction of how climate change can be so devastating.
Murphy, James; Costello, Dan; Zaleski, Martin
The Use of a Geo Pilot Bore to Confirm HDD Feasibility Best Paper Conference
NASTT No-Dig Show, 2023.
@conference{Conference1,
title = {The Use of a Geo Pilot Bore to Confirm HDD Feasibility},
author = {James Murphy and Dan Costello and Martin Zaleski},
url = {https://nastt.org/nastt-announces-2023-outstanding-trenchless-paper-awards-new-installation/},
year = {2023},
date = {2023-03-13},
urldate = {2023-03-04},
booktitle = {NASTT No-Dig Show},
abstract = {Within the Trenchless Program for the Trans Mountain Expansion Project almost 50 Horizontal Directional Drills (HDDs) as well as all the other trenchless methods were utilized. However due to severe topography and access constraints, there were locations where a geotechnical investigation with a normal number of boreholes would not be able to provide sufficient geotechnical information and even a limited number of holes would be cost prohibitive. Boreholes in some cases would have been hundreds of meters deep with difficult access and site preparation. Also, from a design standpoint, engineering would primarily be interested in whether there are fractures that would be major fluid loss zones or there would be fractures or faults that would produce water that would likely fail the HDD. Therefore, for two long ‘potential’ NPS 36, HDD crossings in mountainous terrain, Universal Pegasus offered up the potential for doing ‘geo-pilot bores’ to confirm the feasibility of using HDD in these locations. From a regulatory perspective, a geo-pilot bore following the HDD design profile is considered part of the geotechnical program provided it does not exit and stops short by 50 metres or more. Exiting the bore would constitute “construction” which has significant restrictions and reporting issues. A successful geo-pilot bore approximately 1,700 m (5,600 ft) long confirmed the feasibility of the first HDD crossing at Dry Gulch in August of 2021 and a second geo-pilot bore for the Mountain Crossing #3 HDD crossing, approximately 1,600 m (5,300 ft) long HDD was completed in 2022. This paper describes the design, thinking, and construction challenges behind the geo-pilot bore concept with these two examples.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Within the Trenchless Program for the Trans Mountain Expansion Project almost 50 Horizontal Directional Drills (HDDs) as well as all the other trenchless methods were utilized. However due to severe topography and access constraints, there were locations where a geotechnical investigation with a normal number of boreholes would not be able to provide sufficient geotechnical information and even a limited number of holes would be cost prohibitive. Boreholes in some cases would have been hundreds of meters deep with difficult access and site preparation. Also, from a design standpoint, engineering would primarily be interested in whether there are fractures that would be major fluid loss zones or there would be fractures or faults that would produce water that would likely fail the HDD. Therefore, for two long ‘potential’ NPS 36, HDD crossings in mountainous terrain, Universal Pegasus offered up the potential for doing ‘geo-pilot bores’ to confirm the feasibility of using HDD in these locations. From a regulatory perspective, a geo-pilot bore following the HDD design profile is considered part of the geotechnical program provided it does not exit and stops short by 50 metres or more. Exiting the bore would constitute “construction” which has significant restrictions and reporting issues. A successful geo-pilot bore approximately 1,700 m (5,600 ft) long confirmed the feasibility of the first HDD crossing at Dry Gulch in August of 2021 and a second geo-pilot bore for the Mountain Crossing #3 HDD crossing, approximately 1,600 m (5,300 ft) long HDD was completed in 2022. This paper describes the design, thinking, and construction challenges behind the geo-pilot bore concept with these two examples.
van Veen, Megan; Porter, Mike; Mitchell, Andrew; Funk, Andrew; Watson, Andrew; van Gassen, Wim
The Use of Impact Lines and New Monitoring Tools for Hydro Reservoir Shoreline Hazard and Risk Assessment Conference
SwedCOLD, 2023.
@conference{Conference1,
title = {The Use of Impact Lines and New Monitoring Tools for Hydro Reservoir Shoreline Hazard and Risk Assessment},
author = {Megan van Veen and Mike Porter and Andrew Mitchell and Andrew Funk and Andrew Watson and Wim van Gassen},
year = {2023},
date = {2023-03-12},
urldate = {2023-03-04},
booktitle = {SwedCOLD},
abstract = {The Site C Clean Energy project is the third hydroelectric dam to be constructed on the Peace River in Northeastern British Columbia, Canada. The project is nearing completion and is expected to be operational by 2025. Once completed, the reservoir will flood approximately 83 km of the current river valley. The valley slopes comprise clay-shale bedrock overlain by a complex series of glaciolacustrine and glaciofluvial sediments, which will be subject to increased landsliding and shoreline erosion following impoundment. As part of the project’s Environmental Impact Statement, preliminary reservoir impact lines were developed to delineate areas of potential hazards that may result from reservoir creation. These include flood, erosion, stability, and landslide-generated wave impact lines, supplemented by a shoreline classification system. BC Hydro has developed a series of guidelines for land use within the impact lines, which have been used to guide decisions on re-location of infrastructure and acquisition of rights-of-way throughout the construction process, and future land use planning.
The preliminary impact lines were developed based on modelling, empirical relationships, and engineering judgement, to support decisions around land use and public safety. The most significant erosion impacts are expected to occur within the first several years of reservoir operations, with conditions normalizing over time, whereas the impacts on slope stability may exist well into the reservoir life. The preliminary impact lines will be reviewed and updated following a five-year observation period post-impoundment. A comprehensive monitoring program includes the use of developing technologies such as site-specific and regional-scale lidar change detection, regional-scale satellite-based InSAR, and remote instrumentation, supported by traditional geotechnical instrumentation and field-based observations. New tools are being developed to manage and communicate the monitoring results to a variety of stakeholders.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The Site C Clean Energy project is the third hydroelectric dam to be constructed on the Peace River in Northeastern British Columbia, Canada. The project is nearing completion and is expected to be operational by 2025. Once completed, the reservoir will flood approximately 83 km of the current river valley. The valley slopes comprise clay-shale bedrock overlain by a complex series of glaciolacustrine and glaciofluvial sediments, which will be subject to increased landsliding and shoreline erosion following impoundment. As part of the project’s Environmental Impact Statement, preliminary reservoir impact lines were developed to delineate areas of potential hazards that may result from reservoir creation. These include flood, erosion, stability, and landslide-generated wave impact lines, supplemented by a shoreline classification system. BC Hydro has developed a series of guidelines for land use within the impact lines, which have been used to guide decisions on re-location of infrastructure and acquisition of rights-of-way throughout the construction process, and future land use planning.
The preliminary impact lines were developed based on modelling, empirical relationships, and engineering judgement, to support decisions around land use and public safety. The most significant erosion impacts are expected to occur within the first several years of reservoir operations, with conditions normalizing over time, whereas the impacts on slope stability may exist well into the reservoir life. The preliminary impact lines will be reviewed and updated following a five-year observation period post-impoundment. A comprehensive monitoring program includes the use of developing technologies such as site-specific and regional-scale lidar change detection, regional-scale satellite-based InSAR, and remote instrumentation, supported by traditional geotechnical instrumentation and field-based observations. New tools are being developed to manage and communicate the monitoring results to a variety of stakeholders.
The preliminary impact lines were developed based on modelling, empirical relationships, and engineering judgement, to support decisions around land use and public safety. The most significant erosion impacts are expected to occur within the first several years of reservoir operations, with conditions normalizing over time, whereas the impacts on slope stability may exist well into the reservoir life. The preliminary impact lines will be reviewed and updated following a five-year observation period post-impoundment. A comprehensive monitoring program includes the use of developing technologies such as site-specific and regional-scale lidar change detection, regional-scale satellite-based InSAR, and remote instrumentation, supported by traditional geotechnical instrumentation and field-based observations. New tools are being developed to manage and communicate the monitoring results to a variety of stakeholders.
Koenig, Cassandra; Hilbich, Christin; Hauck, Christian; Arenson, Lukas
Thermal State of Permafrost in the Central Andes Conference
6th European Conference on Permafrost (EUCOP 6), 2023.
@conference{Conference1,
title = {Thermal State of Permafrost in the Central Andes},
author = {Cassandra Koenig and Christin Hilbich and Christian Hauck and Lukas Arenson},
doi = {0.52381/EUCOP6.abstracts.1},
year = {2023},
date = {2023-03-10},
urldate = {2023-03-04},
booktitle = {6th European Conference on Permafrost (EUCOP 6)},
abstract = {The importance of monitoring thermal state of permafrost around the world is well recognized due to the multitude of risks posed by climate change-induced permafrost degradation. International efforts are in place to collate standardized permafrost monitoring data in order to establish an early warning system for the potential consequences of large-scale permafrost loss. Most of these data have been compiled from circumpolar regions and mountain environments in the Northern Hemisphere, with a distinct lack of such monitoring data from the Southern Hemisphere. This has limited evaluations of the thermal state and possible degradation of mountain permafrost in Chile and Argentina within the global context. A compilation of ground temperature datasets from 59 boreholes with depths of up to 100 m established by local industry in high altitude regions of the Central Andes (from 3,500 to 5,500 m in elevation and latitude between 27 °S and 34 °S) is presented. The dataset includes measurements for periods up to 11 years within cold and warm permafrost, where average temperatures at the ground surface are above 0 ⁰C, as well as measurements from non-permafrost zones. Ground temperatures within permafrost zones range from -8 ⁰C to 0 ⁰C below depths of zero annual amplitude. The unique dataset shows a decrease in ground temperature with elevation according to a lapse rate of ~0.4 ⁰C / 100 m altitude, and boreholes installed on south facing slopes are colder than others at the same elevation. Ground temperatures within rock glaciers are significantly lower than ground at similar elevations and tend to be concentrated on south-southwest facing slopes. This is consistent with the expectation that these landforms would delineate the lower limit of permafrost within mountainous environments, providing supporting evidence on the complexity of the ground temperature conditions in the Andes.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The importance of monitoring thermal state of permafrost around the world is well recognized due to the multitude of risks posed by climate change-induced permafrost degradation. International efforts are in place to collate standardized permafrost monitoring data in order to establish an early warning system for the potential consequences of large-scale permafrost loss. Most of these data have been compiled from circumpolar regions and mountain environments in the Northern Hemisphere, with a distinct lack of such monitoring data from the Southern Hemisphere. This has limited evaluations of the thermal state and possible degradation of mountain permafrost in Chile and Argentina within the global context. A compilation of ground temperature datasets from 59 boreholes with depths of up to 100 m established by local industry in high altitude regions of the Central Andes (from 3,500 to 5,500 m in elevation and latitude between 27 °S and 34 °S) is presented. The dataset includes measurements for periods up to 11 years within cold and warm permafrost, where average temperatures at the ground surface are above 0 ⁰C, as well as measurements from non-permafrost zones. Ground temperatures within permafrost zones range from -8 ⁰C to 0 ⁰C below depths of zero annual amplitude. The unique dataset shows a decrease in ground temperature with elevation according to a lapse rate of ~0.4 ⁰C / 100 m altitude, and boreholes installed on south facing slopes are colder than others at the same elevation. Ground temperatures within rock glaciers are significantly lower than ground at similar elevations and tend to be concentrated on south-southwest facing slopes. This is consistent with the expectation that these landforms would delineate the lower limit of permafrost within mountainous environments, providing supporting evidence on the complexity of the ground temperature conditions in the Andes.
Krumm, Eric; Zarnani, Saman
Topographic Amplification Factors for Different Potential Sliding Masses of a Rockfill Dam Conference
Canadian Conference on Earthquake Engineering - Pacific Conference on Earthquake Engineering (CCEE-PCEE), 2023.
@conference{Conference1,
title = {Topographic Amplification Factors for Different Potential Sliding Masses of a Rockfill Dam},
author = {Eric Krumm and Saman Zarnani},
year = {2023},
date = {2023-03-08},
urldate = {2023-03-04},
booktitle = {Canadian Conference on Earthquake Engineering - Pacific Conference on Earthquake Engineering (CCEE-PCEE)},
abstract = {Ground shaking during earthquakes can be affected by local site conditions, which can be separated into two components: soil amplification, due to amplifying or de-amplifying of seismic waves as they pass through the soil, from bedrock to ground surface; and topographic amplification, which refers to the interaction of seismic waves due to the 2D or 3D geometry where the waves travel through. The topographic amplification phenomenon is more complicated to analyze and can be very site specific, due to its truly 2D or 3D nature. For the example of an embankment slope or a dam, the total apparent amplification of the motion between the base of the slope and the crest, is the product of the soil amplification and the topographic amplification. Simplified semi-empirical correlations for estimating permanent seismic displacement during earthquake-induced deviatoric deformations, such as Bray et al. 2018 and Bray and Macedo 2019, use a 1D nonlinear fully coupled stick-slip sliding block. The seismic response of the sliding block is captured by an equivalent-linear viscoelastic modal analysis that uses strain-dependent material properties to capture the nonlinear response of the earth materials. In this way the soil amplification component of the total amplification is captured in the semi-empirical correlation. However, these 1D models can underestimate the seismic demand for shallow sliding masses at the top of 2D systems where topographic amplification can be significant. The objective of this study is to determine topographic amplification factors for the geometry of a rockfill dam for different potential sliding masses, to be used in Bray et al. (2018) type correlations for estimating seismic displacements. The dynamic analyses are performed using FLAC software on a rockfill dam constructed in four different stages. To quantify the soil amplification, 1D soil columns were also created in FLAC mirroring the geometry and stress distribution approximately along the highest dam portion. Following a similar process as Rathje and Bray (2001), a procedure is used for scaling 1D results to account for 2D topographic amplification and averaging of accelerations along different potential sliding masses on a rockfill dam. The results from the 1D columns are then compared to the 2D FLAC results to isolate the topographic amplification effects. The results were benchmarked to case histories reported in the literature. Results show that for shallow sliding masses, topographic amplification factors of up to 1.8 can be expected.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Ground shaking during earthquakes can be affected by local site conditions, which can be separated into two components: soil amplification, due to amplifying or de-amplifying of seismic waves as they pass through the soil, from bedrock to ground surface; and topographic amplification, which refers to the interaction of seismic waves due to the 2D or 3D geometry where the waves travel through. The topographic amplification phenomenon is more complicated to analyze and can be very site specific, due to its truly 2D or 3D nature. For the example of an embankment slope or a dam, the total apparent amplification of the motion between the base of the slope and the crest, is the product of the soil amplification and the topographic amplification. Simplified semi-empirical correlations for estimating permanent seismic displacement during earthquake-induced deviatoric deformations, such as Bray et al. 2018 and Bray and Macedo 2019, use a 1D nonlinear fully coupled stick-slip sliding block. The seismic response of the sliding block is captured by an equivalent-linear viscoelastic modal analysis that uses strain-dependent material properties to capture the nonlinear response of the earth materials. In this way the soil amplification component of the total amplification is captured in the semi-empirical correlation. However, these 1D models can underestimate the seismic demand for shallow sliding masses at the top of 2D systems where topographic amplification can be significant. The objective of this study is to determine topographic amplification factors for the geometry of a rockfill dam for different potential sliding masses, to be used in Bray et al. (2018) type correlations for estimating seismic displacements. The dynamic analyses are performed using FLAC software on a rockfill dam constructed in four different stages. To quantify the soil amplification, 1D soil columns were also created in FLAC mirroring the geometry and stress distribution approximately along the highest dam portion. Following a similar process as Rathje and Bray (2001), a procedure is used for scaling 1D results to account for 2D topographic amplification and averaging of accelerations along different potential sliding masses on a rockfill dam. The results from the 1D columns are then compared to the 2D FLAC results to isolate the topographic amplification effects. The results were benchmarked to case histories reported in the literature. Results show that for shallow sliding masses, topographic amplification factors of up to 1.8 can be expected.