An integrated SEM-Newmark model for physics-based regional coseismic landslide assessment

Earthquake-induced landslides are one of the most catastrophic effects of earthquakes, as evidenced by many historic events over the past decades, such as the 1994 Northridge earthquake in California and the 2008 Wenchuan earthquake in China. Realistic prediction of coseismic landslides is crucial for the design of key infrastructure and to protect human lives in seismically active regions. To date, analytical methods for estimating coseismic landslides have been based on highly simplified models. In this study, an integrated Spectral Element Method (SEM)-Newmark model is developed to directly simulate three-dimensional wave field in complex topography on a regional scale, while the associated landslide is indicated by the Newmark sliding displacement analysis considering key model factors. Topographic amplification, soil response, near-field characteristics of earthquake shaking and hydrogeological conditions can be simulated, and their effects on coseismic landslides are studied. In this paper, two regional-scale case studies were conducted using the developed SEM-Newmark model, including landslide hazard assessment for natural terrain in the western part of Hong Kong island, and the massive landslides occurred during the 2014 M6.5 Ludian earthquake in China. These case studies demonstrated that the proposed integrated model can be effectively used for regional-scale coseismic landslide hazard assessment under various earthquake scenarios and hydrogeological conditions.