Characterization of pre-failure deformation and evolution of a large earthflow using InSAR monitoring and optical image interpretation

• Published in: Landslides Vol. 19; no. 1; pp. 35 - 50
• Main Authors: Yi, Zhang, Xingmin, Meng, Allesandro, Novellino, Tom, Dijkstra, Guan, Chen, Colm, Jordan, Yuanxi, Li, Xiaojun, Su
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2022; Springer Nature B.V
• Subjects: Agriculture; Civil Engineering; Deformation; Earth and Environmental Science; Earth Sciences; Earthquake forecasting; Earthquakes; Emergency communications systems; Environmental monitoring; Failure analysis; Fault lines; Flowslides; Geography; Geomorphology; Hazard assessment; Image resolution; Landslide warnings; Landslides; Landslides & mudslides; Monitoring; Natural Hazards; Original Paper; Rain; Rainfall; Remote sensing; Road construction; Rock falls; Seismic activity; Solifluction; Synthetic aperture radar interferometry; Topography; Transport; Unmanned aerial vehicles; InSAR; Early warning; Deformation; Optical image; Pre-failure; Earthflow
• ISSN: 1612-510X; 1612-5118
• DOI: 10.1007/s10346-021-01744-z

At 6pm on July 19, 2019, the Yahuokou earthflow (Zhouqu County, Gansu Province, China) was reactivated following a period of intense rainfall. A volume of approximately 3.9 × 10 6 m 3 travelled approximately 1100 m in 27 days, blocking part of the Min River. Multi-temporal InSAR monitoring and interpretation of high-resolution optical images were used to map different phase of mass movements (including rock fall, topple, slide, and flowslide) to characterize the pre-failure deformation of the earthflow. Analysis of displacement patterns indicates that initiation of the earthflow is closely correlated with road construction, intense and long-lasting rainfall (443 mm from April 1, to July 19, 2019), and seismic activity. The potential to forecast the time of failure based on pre-failure deformation patterns observed by InSAR monitoring is demonstrated. Three types of pre-failure deformation are distinguished: steady creep, fluctuating creep, and accelerating creep. The monitoring process enabled identification and characterization of three key stages of the earthflow (initiation, transportation, and accumulation/deposition) providing important lessons learned for improvement of landslide early warning and hazard assessment in similar geological and geomorphological settings.