Nepal Earthquake Triggered Landslides Recognition and Deformation Analysis of Avalanches' Region

On April 25th 2015, an Mw 7.8 earthquake occurred near Gorkha, Nepal, which triggered substantial landslides and avalanches in Tibet and Nepal causing severe casualties and economic losses. In this study, based on Landsat 8 images and sub-pixel correlation technology, we acquire horizontal deformation fields of the earthquake region. Combined with the visual interpretation method, we detected the landslides and debris deposition areas of avalanches by extracting the corresponding decorrelation noises. We determined the correlation between the landslides and topography factors. Experimental results show that the extraction of decorrelation noises caused by geohazards from the deformation field, when combined with validation of visual interpretation method, is an effective method for locating the regions effected by landslides and avalanches. Furthermore, results show that landslides are more likely to occur at slope > 30° terrain, both sides of the valley, and high slope is more easily trigger larger single landslides. This study provides a new perspective on detection of earthquake-triggered landslides and debris deposition areas of avalanches, monitoring and early warning of glaciers' velocity based on the Landsat 8 satellite imagery.