56 / 2019-07-04 21:45:09

Landslide Mapping and Monitoring with Multiple InSAR Datasets over Three Gorges Area, China

InSAR,Landslide,monitoring

水库地质灾害防治与生态环境保护 > 地质灾害监测预警

Landslides including rock falls and debris flows exposed great dangers to people’s lives and properties. Wide areas of Three Gorges are identified prone to landslides caused by the vulnerable stratum. The remarkable increases of water level since 2003 significantly affect the stability of slopes along Yangtze River. Besides, the periodical fluctuations of water level and seasonal rainfall make the situation worse. Therefore, slopes stability monitoring in Three Gorges area becomes a vital task for the safety of navigation and local residents.

Traditional displacement monitoring methods such as Global Positioning Systems (GPS) and geodetic leveling cannot be widely applied in the inaccessible mountainous areas. Satellite SAR observation is sometimes the only available tool for slope stability monitoring in these areas. It is important to make full use of the information of SAR images. InSAR methods relying on the phase information from SAR images are mostly applied in slow-moving landslides monitoring with millimeter-level precision. Advanced InSAR methods such as Persistent Scatters InSAR (PS-InSAR) and Small baselines Subsets (SBAS) proposed to overcame the effect of decorrelation and atmospheric turbulence. However, phase unwrapping also becomes a challenging task if large deformation occurs. Compared with InSAR methods, the amplitude based pixel offset tracking and point-like targets offset tracking (PTOT) are more suitable for large displacement measurement with precision of more than 1/10 pixels if high correlations were guaranteed. Usually, high correlations can be kept on point-like targets in vegetated areas.

We will present the strategies we employed for landslide monitoring and mapping. Our InSAR results we obtained from multiple SAR datasets will be cpmpared. After we retrieved the time series deformations on landslides, triggering factors of landslide and deformation mechanisms will be analyzed. Based on our initial results, the water level decline and consecutive rainfall were the most dangerous impact factors for the stability of landslides. Correlations between landslides movement and impact factors are investigated in detail.