Detecting Recent Landslide Activities in Yigong and Surrounding Areas in Eastern Tibet of China Based on GF-3 Sar Amplitude Imagery

Abstract

The study area is located in the north of the Great Bend of Yarlung Zangbo River. Due to unique geological structure and geomorphology environment, landslides occur frequently in this area, for example, the Yigong landslide occurred in 2000 with a volume of 300 million m3, the debris flow in Sedongpu basin in 2018 with a volume of 31 million m3, Dongjiu landslide group and Guxiang gully debris flows et al. Roads, rivers blocks and casualties often caused by landslides activities pose a threat to the lives and property of local people. Due to high altitude and steep terrain of the region, many areas are difficult to reach and remote sensing technology especially high-resolution satellite remote sensing technology could play a significant role in monitoring landslides activities in this region. Frequent earthquake aggravate the activities of landslides, especially after the Ms6.9 Milin earthquake in 18 Nov. 2017. To monitoring regional landslides activities, processed high resolution GF-3 dual-polarization images of multiple periods before and after the earthquake were used to judge landslide activities by using the change detection method and optical images of the same area were used to confirm the interpretation results in the study. The results show that the head part of the Zhamulong Valley shifted significantly, and there several new landslides were detected in the study area. Our method promises to increase the availability of information on landslides in Yigong and surrounding area with benefits for disaster assessment and reducing damage, especially in high mountainous terrain covered by snow and cloud.