A method for seismic landslide hazard assessment using simplified Newmark displacement model based on modified strength parameters of rock mass

Rapid assessment of seismic landslide hazard can provide a scientific basis fordecision-making aimed at post-earthquake emergency response. The Newmark displacement model can quickly assess the seismic landslide hazard after an earthquake without co-seismic landslide inventory. However, as one of the main parameters of the Newmark displacement model, physical and mechanical parameters of the rock mass assigned by traditional methods are too single to reflect the spatial differences of real rock mass strength under complex geological background. To tackle this issue, the distance to the fault, the elevation, and the distance to the river were selected as the evaluation indexes affecting the strength of rock mass, and the evaluation model of rock mass strength was established to obtain the regional rock mass strength modified coefficient, and then the critical acceleration obtained by the traditional method was modified. Combined with the instantaneous peak ground acceleration after an earthquake, the simplified Newmark empirical displacement model was used to calculate the slope cumulative displacement, and the rapid assessment of seismic landslide hazard was conducted. The Wenchuan M_W7.9 earthquake was selected as the studied area to validate the performance of the presented method. Results show that the seismic landslide hazard area divided by the presented method is more consistent with the actual co-seismic landslide distribution compared to traditional method. The presented method in this paper can be used for rapid assessment of seismic landslide hazard, which has important reference value for guiding post-earthquake emergency rescue and land planning and also provides a new idea for the subsequent establishment of a basic geological spatial database.