The use of UAV-based multisource remote sensing in the investigation and monitoring of Jichang landslide in Shuicheng, Guizhou, China

Landslides are one of the common geological disasters in Southwest China. Monitoring the formation and occurrence of landslides and developing prevention strategies are important issues of general interest to scholars in the field of geological disasters. At 8:41 p.m. on July 23, 2019, a destructive rainfall-triggered landslide occurred in Jichang of Shuicheng county, Guizhou province, Southwest China. The location and extent, sliding direction, and other relevant information of this landslide were obtained by visual interpretation from processed multitemporal images captured by unmanned aerial vehicles with real-time kinematics and optical image of the Chinese High-resolution Earth Observation Satellite II. The combination of imaging and pre-landslide and post-landslide images obtained through multisource remote sensing was employed to analyze the landslide characteristics in this work. Geometric correction, atmospheric correction, and orthorectification were applied to the images based on a 1:10,000 topographic map. The landslide volume was estimated from between pre-landslide and post-landslide digital elevation models. The findings showed that the projection area of the landslide was 32.0 × 10 m. This landslide had a total runout distance of 1350 m along a vertical distance of approximately 499 m, and the total duration of the landslide was 60 s with an average velocity of 22.5 m/s. The landslide involved slope failure of approximately 1.8 million m. An unspoiled mound with a surface area of 2.07 × 10 m was detected in the middle and lower parts of the Jichang landslide. The landslide could be characterized by a long runout and high position, induced mostly due to heavy rainfall and comprehensive disasters involving landslide and rock-debris flow. There is a potential failure risk of this landslide, and it is recommended to strengthen the precaution system employed for slope observation and mass prevention, so as to protect the lives and properties of residents.