Coseismic landslides can destroy buildings, dislocateroads, sever pipelines, and cause heavy casualties. It is thus important butchallenging to accurately map the hazards posed by coseismic landslides.Newmark's method is widely applied to assess the permanent displacementalong a potential slide surface and model the coseismic response of slopes.This paper proposes an improved Newmark analysis for mapping the hazards ofcoseismic landslides by considering the roughness and effect of the size of thepotential slide surfaces. This method is verified by data from a case studyon the 2014 Mw?6.1 (the United States Geological Survey) Ludianearthquake in Yunnan Province, China. Permanent displacements due to theearthquake ranged from 0 to 122 cm. The predicted displacements werecompared with a comprehensive inventory of landslides triggered by theLudian earthquake to map the spatial variation in the hazards of coseismiclandslides using the certainty factor model. The confidence levels ofcoseismic landslides indicated by the certainty factors ranged from ?1 to0.95. A hazard map of the coseismic landslide was generated based on thespatial distribution of values of the certainty factor. A regression curverelating the predicted displacement and the certainty factor was drawn, andcan be applied to predict the hazards of coseismic landslides for anyseismic scenario of interest. The area under the curve was used to comparethe improved and the conventional Newmark analyses, and revealed theimproved performance of the former. This mapping procedure can be used topredict the hazards posed by coseismic landslides, and provide guidelinesfor decisions regarding the development of infrastructure andpost-earthquake reconstruction.
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