Kinematic Behavior Analysis of the Wadi Landslide From Time-Series Sentinel-1 Data

The analysis of kinematic characteristics and triggering factors of the potentially unstable slopes is of great significance for the slope protection and landslide reinforcing. Located in Mao Country, Sichuan Province in China, Wadi village is a typical mountainous area where geological disasters frequently occur due to the complex geological environment, intense tectonic activities, and concentrated seasonal rainfall. However, the slope stability and potential risk over this area are not fully evaluated yet. In this article, we investigate the unstable slope in Wadi village using time-series synthetic aperture radar interferometry (InSAR) technique. The deformation history retrieved from 132 C-band descending Sentinel-1 images between October 2014 and September 2019 demonstrates that the Wadi landslide presents a slow sliding trend with the averaged line-of-sight velocity of -70 mm/year and has a distinct seasonal velocity at the head and toe area. We further decompose the predominant and periodic velocities by a kinematic model to analyses spatial and temporal characteristics of Wadi landslide. The results reveal that the Wadi landslide is a hybrid type of push and pull with two source areas in the head and toe of the slope, respectively. The periodic velocity variations are highly correlated with seasonal rainfall. Our study also demonstrates the importance of correcting InSAR unwrapping error for interpreting the landslide kinematics and other small-scale geomorphological processes.