On September 10, 2005, a landslide occurred to the south of Utah State University Campus and Highway 89. This landslide did considerable damage to the Logan and Northern canal, which is cut into the slope, and to a residence at the toe of the slope. This event brought many parties together to collaborate on possible solutions to the immediate fix of the slide as well slides that could occur in the future. The purpose of this report is to compile information useful to the study of the area and the possible solutions and/or risk assessment of the Logan Bluff Landslide Zone. The study includes the records of any landslides, possible causes of slope failures, historical precipitation analysis, construction and land use changes over time, and a specific study of the September 2005 slide. The information presented in this report still leaves many questions unanswered and other data is likely available. However, it can be used as the starting point for a more in depth study of the bluff area.

Social constructions, or frames, often determine how and to whom benefits and burdens are delivered by public policy. Triggering events often open policy windows in which drastic policy changes can occur. In July of 2009, a wet, steep hillside failed in Logan, Utah, leveling a home below and destroying an irrigation canal that ran along the hill. The resulting policy changes illustrated how social constructions of agricultural producers in terms of deservedness and power shifted, both as a result of urbanization and as a result of the landslide. Policy processes are often path-dependent and decisions can become self-reinforcing. Analyzing the pathway that led up to the landslide provided insights into the importance of proactive management and long-term planning of water infrastructure, especially in urbanizing environments. By using policy and discourse analysis, this thesis highlights water management challenges involved in the urbanizing arid U.S. Intermountain West and how planners and policymakers can use this information to achieve democratic policy solutions.

No description available.

Understanding the interplay between surficial and tectonic processes in the development of Utah's Wasatch Range is vital to evaluating geologic hazards along the Wasatch Front. Baldy is a large (6.125 km3) block of limestone and sandstone structurally overlying shale on the western flank of Mount Timpanogos. It has been mapped as a downdropped normal fault block of Permian units, but no other trace of such a fault exists along the range. The Baldy block structurally overlies the weak Manning Canyon shale, which has produced a regional geomorphology replete with faceted spurs, landslide scarps and deposits. Structural, bio- and litho-stratigrahic mapping of the block reveals breccia deposits, bed rotation and stratigraphic and structural relations to Mount Timpanogos consistent with a landslide interpretation. Structural reconstructions of the block and calculations of stream downcutting rates help constrain the timing and sequence of events of the block's emplacement. These results attest to the importance of surficial processes in the development of large-scale geologic structures, and demonstrate the ongoing danger of mass wasting to the communities of the Wasatch Front.

Wildfires result in altered landscape as well as altered soil properties. Wildfires result in conditions that are more susceptible to geotechnical hazards introducing a potential for cascading events in the surrounding area. Shallow landslides are common geohazards that result in a post-wildfire landscape. With an ever-increasing trend in wildfires, the need to better understand the impact wildfire-altered soil properties play on shallow slope instability is critical to evaluating risks to existing or planned development, mitigation of potentially hazardous conditions, prioritization of post-wildfire planning, and post-wildfire response preparation. The primary objective of this study is to provide a comprehensive overview of wildfire-altered geotechnical soil properties and their impact on rainfall-triggered landslides. For this purpose, laboratory and field testing has been performed on soil samples collected from four wildfire areas in California. In-situ hydraulic conductivity tests were performed on both burned and unburned soil. Soil samples collected from burned and unburned areas were tested in for index properties, shear strength, organic content, and pH. Results show that the mean angle of internal friction was reduced in burned soil samples for all study areas, the mean pH, organic content, and hydraulic conductivity were all greater in burned soils in all study areas, and cohesion was found to have contradicting trajectories. Resulting soil properties have been used to compare the factors of safety for representative unburned and burned slopes using a finite element seepage analysis and limit equilibrium slope stability analysis. The unburned and burn soil sample results are used to determine relative factors of safety for slope stability at each of the four wildfire areas. Peak historic and predicted precipitation have been used to further evaluate the relative factors of safety for pre and post-wildfire slope stability conditions. The comparative slope stability analysis has been used to provide a quantitative comparison of the role altered soil properties play on the potential for slope instability. Through this study, it is apparent that although soil properties are altered by wildfire, the impact altered soil properties have on the subsequent slope instability is much less than that of other contributing factors, including precipitation and root support.

The creation of landslide inventories is an important step in landslide susceptibility mapping, and automated algorithms for landslide detection will increasingly be relied upon as part of the mapping process. This study compares the effects of three different DTM generation methods on a pixel-based landslide detection algorithm developed by Shi et al. (2018) using a set of landslide-prone study areas in Pierce County, Washington. Non-parametric statistical analysis demonstrated that false-positive and false-negative rates were significantly different between DTM generation methods, showing that inpainting presents a more balanced error profile compared to TIN and morphological-based approaches. However, overall accuracy (kappa) rates were still very low overall, suggesting that geomorphometric curvature as an input needs to be processed in a different manner to make these types of pixel-based landslide detection algorithms more useful for landslide inventory database management. / Master of Science / The creation of landslide inventories is an important step in landslide susceptibility mapping, and automated algorithms for landslide detection will increasingly be relied upon as part of the mapping process. This study compares the effects of three different DTM generation methods on a pixel-based landslide detection algorithm developed by Shi et al. (2018) using a set of landslide-prone study areas in Pierce County, Washington. Statistical analysis demonstrated that false-positive and false-negative rates were significantly different between DTM generation methods, showing that inpainting presents a more balanced error profile compared to TIN and morphological-based approaches. However, overall accuracy rates were still very low overall, suggesting that curvature as an input needs to be processed in a different manner to make these types of pixel-based landslide detection algorithms more useful for landslide inventory database management.

published_or_final_version / abstract / Applied Geosciences / Master / Master of Science

River blockages formed by rock avalanches appear to pose a higher hazard potential than other landslide dams, given the extreme run-out distances and volumes of rock avalanche deposits. Recent research has identified rock avalanche deposits to have internal sedimentology consisting of a coarse surficial material (carapace) and a finer fragmented interior (body) potentially of critical importance to rock-avalanche dam stability. Physical scale modelling of overtopping failure and breach development in rock avalanche dams was used to quantify the influence of this sedimentology on critical breach parameters, and their prediction using existing embankment dam breach technologies. Results from this study indicate that the time to failure for rock avalanche dams is approximately twice that observed for homogeneous dams due to the armouring properties of the carapace; and that peak discharge is not significantly affected by sedimentology. While application of empirical, parametric, dimensional and physically based models indicated that uncertainty associated with predicted dam break discharges could range from ±19% to ±107%, no modelling technique was able to simulate the armouring phenomenon adequately. Comparison of actual and simulated breach evolution shows linear assumptions of breach depth and width development (as observed in homogeneous dams) to be incorrect. In the context of hazard management, the results suggest that empirical regression relationships should be used for rapid assessment of potential dam break flood magnitude.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23711号 / 理博第4801号 / 新制||理||1688(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 王 功輝, 教授 釜井 俊孝, 教授 久家 慶子 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Thesis (M. App. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 176-185). Also available in electronic format on the Internet.