Impacts of potential seismic landslides on lifeline corridors.

PDFTech ReportFHWA-OR-RD-15-06SPR 740Seismic prospectingLandslidesEarthquakesHazard analysisMappingProbabilityHighway corridorsLifelinesRisk assessmentOregonOregon. Dept. of Transportation. Research SectionOlsen, Michael J.Ashford, Scott A.Mahlingam, RubiniSharifi-Mood, MahyarO\uc2\ubfBanion, MattGillins, Daniel T.Oregon State University. School of Civil and Construction EngineeringUnited States. Federal Highway AdministrationUS Transportation CollectionThis report presents a fully probabilistic method for regional seismically induced landslide hazard analysis andmapping. The method considers the most current predictions for strong ground motions and seismic sourcesthrough use of the U.S.G.S. seismic hazard curves in conjunction with topographic, geologic, and othergeospatial information. Probabilistic landslide triggering analysis is performed based on Newmark\ue2\u20ac\u2122s slidingblock theory. Because strength parameters are difficult to obtain in detail for a large regional area, frictionangles for each lithological unit are estimated from histograms of the terrain slope at locations of previouslymapped landslides within the unit. Afterwards, empirical models are used to predict the probability of alandslide triggering and the probability of horizontal displacement from a landslide exceeding specific thresholds(i.e., 0.1, 0.3, 1.0 m) relevant to engineering and planning purposes.The probabilistic landslide-triggering map is evaluated by comparing its predictions with previously mappedlandslides from the Statewide Landslide Inventory Database of Oregon (SLIDO). Over 99.8% of the landslidesin SLIDO are located in areas mapped with very high probability (i.e., 80-100%) of a landslide triggering.The created landslide hazard maps are suitable for regional resilience and planning studies by various agencies,as well as integration with maps of other types of hazards for probabilistic-based multi-hazard calculations andrisk assessment. The maps should not be used in place of site-specific analyses, but may be used to prioritizewhere site-specific analyses and new geotechnical investigations are most needed. Finally, the maps can be usedto identify which sections of the highway corridors would be likely be least affected by landslides, enabling it toserve as a lifeline rout