Lifecycle of the 21 July, 2020 Shaziba landslide investigated using multi-source remote sensing observation

Shallow landslides and debris flows triggered by high-intensity continuous precipitation are widespread in the  western part of Hubei province, China. Studies have also shown that most of the landslides in western Hubei belong to the category of  slow-moving landslides that impact infrastructures and can eventually turn into catastrophic failures. Although many landslides cannot be prevented, some possible scientific early warning detection and landslide evolution analysis before and after the failure can help in risk management practices. Under favorable conditions, optical and Synthetic Aperture Radar (SAR) satellite remote sensing data  play a key role in robust characterization of life cycles of slow moving landslides. In this study, we utilized various SAR and optical sensors to investigate kinematic evolution and volumetric change related to the 21 July, 2020, the Shaziba landslide that occurred in Mazhe County, Hubei Province, China (N 30° 36′ 5′′, E 109° 29′ 85′′). The catastrophic failure happened  following a record precipitation that reached a historical peak of 442.3 mm in the month of failure, exceeding the previous historical peaks in the same month. This landslide caused the collapse of more than 60 homes, the destruction of village roads, the destruction of electrical infrastructure and agriculture, the evacuation of more than 1000 individuals, and the pollution of Enshi City's water supply source with silt. Fortunately, there were no fatalities. The pre-failure ground deformation using Sentinel-1 data from June 2016 to July 2020 indicates ground motions at average rates of 30 mm/yr. The co-failure estimation from Planet and Sentinel-2 shows that horizontal displacements in the eastern part of the landslide up to 30 m. The landslide eroded to 4.93 million m3 meters, with DEMs generated from TanDEM-X data before and after the failure. The post-failure ground deformation analysis performed using Sentinel-1 and TerraSAR-X data between August 2020 to July 2021 indicated the instability of the marginal scarps above the crown of landslide and eastern, with an LOS displacement rate of approximately -30 - -10 mm/year.