Characterization of Ground Deformation Associated with Shallow Groundwater Processes Using Satellite Radar Interferometry

Shallow groundwater processes maylead to ground deformation and even geohazards. With the features of day-and-night accessibility and large-scale coverage, time-series interferometric synthetic aperture radar (InSAR) has proven a useful tool for mapping the deformation over various landscapes at cm to mm level with weekly to monthly updates. However, it has limitations such as, decorrelation,atmospheric artifacts, topographic errors, andunwrapping errors, in particular for the hilly, vegetated, and complicated deformation patterns. In this dissertation, I focus on characterizing the ground deformation over landslides, aquifer systems, and mine tailings impoundment, using the designed advanced time-series InSAR strategy, as well as theinterdisciplinary knowledge of geodesy, hydrology, geophysics, and geology. Northwestern USA has been exposed to extreme landslide hazards due to steep terrain, high precipitation, and loose root support after wildfire. I characterize the rainfall-triggered movements of Crescent Lake landslide, Washington State. The seasonal deformation at the lobe, with larger magnitudes than the downslope riverbank, suggests an amplified hydrological loading effect due to a thicker unconsolidated zone. High-temporal-resolution InSAR and GPS data reveal dynamic landslide motions. Threshold rainfall intensities and durations wet seasons have been associated with observed movement upon shearing: antecedent rainfall triggered precursory slope-normal subsidence, and the consequent increase in pore pressure at the basal surface reduces friction and instigates downslope slip over the course of less than one month. In addition, a quasi-three-dimensional deformation field is created using multiple spaceborne InSAR observations constrained by the topographical slope, and is further used to invert for the complex geometry of landslide basal surface based on mass conservation. Aquifer skeletons deform in response to hydraulic head changes with various time scales of delay and sensitivity. I investigate the spatio-temporal correlation among deformation, hydrological records and earthquake records over Salt Lake Valley, Utah State. A clear long-term and seasonal correlation exists between surface uplift/subsidence and groundwater recharge/discharge, allowing me to quantify hydrogeological properties. Long-term uplift reflects the net pore pressure increase associated with prolonged water recharge, probably decades ago. The distributions of previously and newly mapped faults suggest that the faultsdisrupt the groundwater flow andpartition hydrological units. Mine tailings gradual settle as the pore pressure dissipates and the terrain subsides, andtailings embankment failures can be extremely hazardous. I investigate the dynamics of consolidation settlement over the tailings impoundment in the vicinity of Great Salt Lake, Utah State, as well as its associated impacts to the surrounding infrastructures. Largest subsidence has been observed around the low-permeable decant pond clay at the northeast corner.The geotechnical consolidation model reveals and predicts the long-term exponentially decaying settlement process. My studies have demonstrated that InSAR methods can advance our understanding about the potential anthropogenic impacts and natural hydrological modulations on various geodynamic settings in geodetic time scale

Hillslope memory and spatial and temporal distributions of earthquake-induced landslides

Large earthquakes commonly trigger widespread and destructive landsliding. However, current approaches to modeling regional-scale landslide activity do not account for the temporal evolution of progressive failure in brittle hillslope materials. Progressive failure allows hillslopes to possess a memory of previous earthquakes, which has the potential to influence landslide activity in future earthquakes. The original contribution of this thesis is to address the influence of hillslope memory on spatial and temporal patterns of earthquake-triggered landslide activity, through a combination of landslide inventory analysis and numerical modeling. An understanding of spatial distributions of earthquake-triggered landslides is first established, through analysis of inventories of landslides triggered by five large (M_w > 6.7) earthquakes. The results show how current landscape conditions at the time of earthquakes influence hillslope failure probability. By identifying factors exhibiting a common influence on landslides triggered by all five earthquakes, general spatial models of landslide probability are developed, which are transferrable between different earthquakes and regions. Analysis of model performance for landslide distributions triggered by two sequential earthquakes is then used to establish where this spatial approach breaks down. Errors in the landslide distribution predicted for the second earthquake suggest that the legacy of damage to hillslope materials accrued from the first earthquake is an important control on landslide occurrence. Given the infrequent recurrence of large earthquakes and limited temporal coverage of landslide data, a new modelling approach is developed to understand how hillslope memory influences long-term patterns of earthquake-triggered landslide activity. The model integrates the site-scale evolution of hillslope progressive failure into modeling regional-scale earthquake-triggered landslide activity, in response to sequences of earthquakes. The model results suggest that the sensitivity of landscapes to landslide-triggering increases following large earthquakes, due to damage accumulated in hillslopes that do not reach the point of failure, and decays as these hillslopes fail in response to subsequent, lower-magnitude events. Prolonged elevated levels of rainfall-triggered landslide activity observed following large earthquakes appear to reflect this result. Using the model outputs, a methodology is proposed for predicting temporal variability in landslide activity using records of seismic data. The model results also suggest that, when hillslopes undergo progressive failure, relationships between seismic forcing and landslides are influenced by the magnitude-frequency distribution of earthquakes. As a result, current approaches that use these relationships to predict levels of long-term landslide hazard and erosion rates, but do not account for regional differences in earthquake distributions, may suffer from systematic under- or over-prediction. These significant implications for predicting the geomorphological and human impact of landslides highlight the need for detailed multi-temporal datasets recording the evolution of landslide activity following major earthquakes, in order to quantitatively investigate the influence of hillslope memory in real landscape settings

Regional and Site-Specific Vulnerabilities of the Western Power Grid from a M9.3 Cascadia Subduction Zone Earthquake

The likelihood of a Cascadia Subduction Zone (CSZ) earthquake is estimated between 37 to 42% in the next 50 years, leading to strong shaking, liquefaction, landsliding, and other seismic ground failure resulting in major impacts to critical lifelines such as the western power grid. Electrical power is essential for continued functionality of emergency services, economic recovery, and other basic, essential needs such as water and fuel supply, wastewater treatment, and communications. Hence, understanding the extent of damage to the power grid from a CSZ event is critical. The objective of this research, part of a broader study identifying the seismic resilience of the western power grid, is to assess the vulnerabilities of the synthetic western power grid by quantifying the likelihood and magnitude of seismically induced landslide occurrence to determine the effects of those displacements on electrical transmission poles and towers at a regional scale. To this end, this thesis presents a probabilistic method for a regional seismic landslide hazard analysis and map for the Western United States based on the USGS M9.3 Megathrust CSZ scenario earthquake with consideration of topographic, geologic, and other geospatial information. The landslide triggering analysis completed uses several empirical seismic displacement prediction models based on the Newmark sliding block method, which are calibrated using strength parameters for each geological unit based on the terrain slope at locations of previously mapped landslides within the unit. A predictive displacement regression model, LOS21 was developed using a logic tree scheme that weights the individual models based on the suitability of the model to this regional assessment. The LOS21 model was used to calculate the probability of exceedance of specific thresholds (e.g., 5%, 15% and 50%) to evaluate potential impacts to the power grid. Electrical infrastructure located west of the Cascades in Washington, Oregon, and Northern California were determined to be subjected to the highest risk of landslide-induced damage. To provide context to the broader study focusing on non-landslide-induced impacts to the western power grid (e.g., ground shaking and inertial equipment loading), an evaluation site was characterized for a detailed site-specific site response analyses to evaluate the differences in amplification between equivalent linear and nonlinear, total stress analyses using ten ground motions pairs scaled and matched to the USGS seismic scenario hazard. The results of the site-specific site response analysis are used to evaluate the potential impact to the electrical components for the substation at the evaluation site for comparison to the seismic hazard developed using the regional map. The equivalent linear and the nonlinear approach produced PGA amplification results that were lower from the USGS seismic scenario hazard by 6% and 32%, respectively. The maps created are suitable for regional resilience and planning and to guide geotechnical investigations but should not be used in place of site-specific analysis for engineering design purposes

Probabilistic Geospatial Analyses, Uncertainty Modeling, and Mapping of Seismically-induced Ground Failures

Ground failures, in particular landsliding, liquefaction and lateral spreading can be triggered by seismic sources. The frequency, magnitude, and impact of these ground failures are highly dependent on the topography and geology of the site including its slope, depositional environment, and geotechnical properties as well as the proximity of the site to seismic sources. Many available models for estimating these variables have high epistemic uncertainty given the extreme challenge to fully characterize seismic sources and subsurface conditions. Nevertheless, this high uncertainty must be considered when mapping ground failure hazards for a large area using geologic, geotechnical, topographical, and seismic hazard data of limited availability.Many hazard maps do not fully consider uncertainty from the seismic sources, subsurface testing, and empirical models developed for estimating ground failures. Often, previously developed maps are qualitative based on judgment due to the lack of detailed subsurface geotechnical investigations.This research presents new mapping methods to address these challenges, resulting in ground failure hazard maps for evaluation and risk assessment. It explores both deterministic and probabilistic methods of mapping ground failure hazards for large study areas. Available geospatial data are incorporated in this research including digital elevation models (DEMs) acquired from lidar and photogrammetric data, DEM derivatives such as slope, geologic mapping, shear wave velocity tests and other geotechnical subsurface investigations, and seismic hazard curves.First, efficient algorithms were developed to map estimates of the peak ground acceleration, landslide and liquefaction triggering probability, and horizontal displacement as a result of landslides or lateral spreading across the state of Oregon for several earthquake scenarios associated with the Cascadia Subduction Zone (CSZ). These algorithms utilize site classification and site geology maps provided by the Oregon Department of Geology and Mineral Industries (DOGAMI).Second, a performance-based, landslide-induced, displacement hazard mapping technique is proposed and implemented for Western Oregon. This approach computes landslide displacement hazard curves across the regional area. The approach utilizes a detailed landslide inventory database and high-resolution topographical data to estimate the soil strength and associated uncertainty in the general geologic units. Third, in an effort to characterize the uncertainty of the geotechnical properties of geologic units, a geospatial geotechnical database was developed and evaluated. In this evaluation, available geologic maps and geotechnical subsurface databases from three counties in the State of Utah were compiled. Then, several distributions of geotechnical properties for the general geologic units were developed, and these distributions enabled the determination of which geologic units were most susceptible to liquefaction and lateral spreading. A statistical approach was also developed to provide a framework for simplifying geologic units based on soil properties.Lastly, a new and fully probabilistic framework is developed for mapping the liquefaction-induced lateral spread displacement hazard at a regional scale. This framework is demonstrated by producing lateral spread hazard maps for Utah County, Utah. By performing numerous Monte Carlo simulations, the method accounts for uncertainties in the soil properties, seismic loading, and the empirical models for predicting horizontal displacements due to lateral spreading.Keywords: Liquefaction, Ground Failure, Landslide, Lateral Spreading, Earthquake, Hazard Mappin

Predictive geohazard mapping using LiDAR and satellite imagery in Missouri and Oklahoma, USA

”Light Detection and Ranging (LiDAR) and satellite imagery have become the most utilized remote sensing technologies for compiling inventories of surficial geologic conditions. Point cloud data obtained from multi-spectral remote sensing methods provide a detailed characterization of the surface features, in particular, the detailed surface manifestations of underlying geologic structures. When combined, point clouds eliminate bias from visual inconsistencies and/or statistical values. This research explores the competence of point clouds derived from LiDAR and Unmanned Aerial Systems (UAS) as a predictive tool in evaluating various geohazards. It combines these data sets with other remote sensing techniques to evaluate the sensitivity of the respective datasets to temporal changes in the earth’s surface (potentially detectable at a centimeter-scale). A two-phase research approach was employed to test several hazard mapping scenarios in three geographic areas in the U.S. Midcontinent as follows: 1) UAS-derived surficial deformations near the epicenter of the 2016 Mw 5.8 Pawnee, Oklahoma earthquake (Paper I); 2) UAS mapping of recent earthquake epicenters in Noble Payne and Pawnee counties of Oklahoma State (Paper II); and, 3) Evaluation of geohazards in Greater Cape Girardeau Southeast Missouri (Paper III). These analyses detected geomorphic changes in the study locations, such as ground subsidence, soil heave and expansion, liquefaction-induced structures, dynamically-induced consolidation, and surface fault rupture. The studies underscore the importance of early hazard identification and providing information to relevant data users to make informed decisions”--Abstract, page iv

Selected Papers from the 11th Asian Rock Mechanics Symposium (ARMS 11)

The problem of rock mechanics and engineering is an old and new subject encountered by human beings in their struggle with nature for survival and development. To call it ancient means that it has a long history; however, speaking of it as brand-new refers to the continuous emergence of new problems and new situations in engineering practice, which is quite challenging. With the development of human engineering activities, the issues surrounding rock engineering are becoming more and more prominent, and the problems encountered are becoming more and more complex. In the practice of solving complex rock engineering, human beings have summarized many topics that are difficult to explain or solve with classical mechanics

Soil-Water Conservation, Erosion, and Landslide

The predicted climate change is likely to cause extreme storm events and, subsequently, catastrophic disasters, including soil erosion, debris and landslide formation, loss of life, etc. In the decade from 1976, natural disasters affected less than a billion lives. These numbers have surged in the last decade alone. It is said that natural disasters have affected over 3 billion lives, killed on average 750,000 people, and cost more than 600 billion US dollars. Of these numbers, a greater proportion are due to sediment-related disasters, and these numbers are an indication of the amount of work still to be done in the field of soil erosion, conservation, and landslides. Scientists, engineers, and planners are all under immense pressure to develop and improve existing scientific tools to model erosion and landslides and, in the process, better conserve the soil. Therefore, the purpose of this Special Issue is to improve our knowledge on the processes and mechanics of soil erosion and landslides. In turn, these will be crucial in developing the right tools and models for soil and water conservation, disaster mitigation, and early warning systems

The Methodologies and Main Challenges of Assessment the Multi-Hazard Interaction and Risk Management Associated with Roads Infrastructures and Dam Safety: A Review

The idea of multi-hazard interactions and risk assessment, particularly in relation to both natural hazards and hazards triggered by anthropogenic processes, has been widely used, especially in recent decades. Numerous areas worldwide, as well as various sectors, face exposure to multiple hazards. These hazards encompass natural phenomena like floods, earthquakes, hurricanes, and more. In comparison, the human-induced or anthropogenic processes associated with infrastructure development, along with other potential human activities such as, land and cover use change, contribute to the overall hazard landscape. Both natural hazards and anthropogenic-induced directly led to infrastructure collapse and loss of functionality with other consequences for human lives, economy, beside the environment impacts. Limited studies have been conducted on the implementation of the comprehensive multi-hazard interaction approach, which is globally or regionally required, along with detailed studies on the interaction between different multi-hazard sources and their interrelationships in short-term or long-term scenarios. The current research aims to review previous literature and studies on the multi-hazard interaction approach, methodologies of visualization and classification, as well as explores the potential of multi-hazard associated with road networks, infrastructures, and dams. The research utilizes simulation various models and tools such as, Geographic Information System (GIS) beside Remote Sensing (Rs) techniques. The current study concludes that using multi-hazard maps, hazard matrix, and fragility curves represents highly valuable and very useful and flexible tools for implementing and visualization hot spot areas exposure by multi-hazard consequences and vulnerability analysis for short and long-term scenarios. In addition, the current review highlighted for development a holistic conceptual framework for multi-hazard and risk assessment associated with hydraulic structures such as dams, road networks and infrastructures with hazard exposure analysis to be used as tools for a decision support system (DSS) in order to develop urban resilience, risk management and hazard mitigations