PRELIMINARY RESULTS AND ANALYSES OF POST-EARTHQUAKE GEOLOGICAL HAZARDS IN JIUZHAIGOU BASED ON AIRBORNE LIDAR AND IMAGERY
A magnitude 7.0 earthquake struck Jiuzhaigou County, Sichuan Province at 21:00 on August 8, 2017, and the epicentre was located in the major tourist spot of Jiuzhaigou. This paper describes the surveying and mapping project of post-earthquake hazards regions for the restoration and reconstruction purposes. The earthquake triggered thousands of collapses and landslide disasters, causing severe damage to tourist land scapes and scenic roads such as Jiuzhaigou Panda Sea. The geological hazards of steep mountains and steep slopes and dense vegetation in the scenic area are highly concealed. Traditional susceptibility mapping methods for geological hazard using only airborne images have encountered great difficulties. Aiming to solve this issue, airborne LiDAR and high-resolution images were used jointly to interpret geological disasters in this area. The three-dimensional interpretation signs of disasters are established comprehensively by using optical images and digital elevation models to obtain the distribution characteristics of existing geological hazards, coseismic geological hazards and hidden dangers, which support the restoration and reconstruction of the tourist spots.