Study on Earthquake-Triggered Landslide Hazard Assessment Under Rainfall Condition

Landslides’ occurrence results from not only the environmental background conditions of slopes, but also triggering factors, such as rainfall and earthquake etc. This study selected Pengzhou, Dujiangyan, Chongzhou and Dayi cities as the research area, which were affected severely by Wenchuan Ms 8.0 Earthquake. At the aim of assessing regional landslide hazard under the conditions of heavy rainfall and Ms 8.0 earthquake, Newmark model and hydrological distribution model were adopted based on GIS technology. First, the whole study area was divided into cells with grid size 30 m × 30 m and the Newmark displacement of each grid in the region was calculated under the roles of heavy rainfall and earthquake. And then, make a coupling analysis between the Newmark displacements and landslides inventory map to establish a curve equation, which will give the hazard degree to each grid. Finally, the earthquake-triggered landslide hazard assessment map was completed. The result shows that the moderate and high hazardous regions cover 37.1 % area and are containing about 82 % landslides. The landslide density has a great relationship with hazard degree and it is increasing with the hazard level increase, which implies the result is accord with the reality and can be used to provide the research foundation for the landslide risk management and the reference for the regional reconstruction planning.