NH43D-05
PROBABILISTIC, SEISMICALLY-INDUCED LANDSLIDE HAZARD MAPPING OF WESTERN OREGON

Thursday, 17 December 2015: 14:40
309 (Moscone South)
Mahyar Sharifi Mood1,2, Michael J Olsen3, Daniel T Gillins3 and Rubini Mahalingam4, (1)Oregon State University, Civil and Construction Engineering, Corvallis, OR, United States, (2)American Geophysical Union, Washington, DC, United States, (3)Oregon State University, School of Civil and Construction Engineering, Corvallis, OR, United States, (4)PhD graduate, Coimbatore, India
Abstract:
Earthquake-induced landslides can generate significant damage within urban communities by damaging structures, obstructing lifeline connection routes and utilities, generating various environmental impacts, and possibly resulting in loss of life. Reliable hazard and risk maps are important to assist agencies in efficiently allocating and managing limited resources to prepare for such events. This research presents a new methodology in order to communicate site-specific landslide hazard assessments in a large-scale, regional map. Implementation of the proposed methodology results in seismic-induced landslide hazard maps that depict the probabilities of exceeding landslide displacement thresholds (e.g. 0.1, 0.3, 1.0 and 10 meters). These maps integrate a variety of data sources including: recent landslide inventories, LIDAR and photogrammetric topographic data, geology map, mapped NEHRP site classifications based on available shear wave velocity data in each geologic unit, and USGS probabilistic seismic hazard curves. Soil strength estimates were obtained by evaluating slopes present along landslide scarps and deposits for major geologic units. Code was then developed to integrate these layers to perform a rigid, sliding block analysis to determine the amount and associated probabilities of displacement based on each bin of peak ground acceleration in the seismic hazard curve at each pixel. The methodology was applied to western Oregon, which contains weak, weathered, and often wet soils at steep slopes. Such conditions have a high landslide hazard even without seismic events. A series of landslide hazard maps highlighting the probabilities of exceeding the aforementioned thresholds were generated for the study area. These output maps were then utilized in a performance based design framework enabling them to be analyzed in conjunction with other hazards for fully probabilistic-based hazard evaluation and risk assessment.

a) School of Civil and Construction Engineering, Oregon State University, Corvallis, OR 97331, USA

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