67 / 2019-07-24 10:17:35

Recent deformation of Yangjiao fossil landslide (China) investigated with L- and X-bands SAR images

Yangjiao Landslide; MT-InSAR; CR-InSAR

水库地质灾害防治与生态环境保护 > 地质灾害监测预警

Abstract: Yangjiao landslide in the south of Chongqing City (China) is a typical fossil landslide, which is mainly filled with the rockslide deposits. Recently, the phenomenon of slope movement was observed by local residents, such as ground fissure, threatening the security of their lives and properties. With the purpose of giving early warning and reducing the landslide damage, this study tried to use the multitemporal interferometric synthetic aperture radar (MT-InSAR) techniques to investigate the recent deformation of this potential landslide area.
In this investigation, two kinds of SAR data including L-band ALOS/PALSAR and X-band TerraSAR images were collected to produce the deformation map over the experimental region. These multi-band SAR data sets with different imaging parameters, e.g. azimuth and incidence angle, spatial and temporal resolution, orbit direction, wavelength, allowed us comprehensively to compare and analyze observed slope deformation since they could show the different characters in maximum detection gradient, degree of decorrelation, capability of noise rejection, etc. Meanwhile, the LiDAR DEM with spatial resolution of 1 m and height precision of 0.1 m was employed to remove the topographic phase during the process of MT-InSAR.
In this experiment, the deformation rate in line-of-slight (LOS) direction from L- and X-bands SAR images was firstly generated to locate the landslide. In this process, the ability of L- and X-band SAR images in observing the landslide deformation was compared and discussed, such as the density of coherence points, precision of the LOS deformation rate. Then, the time series deformation was produced. This result allowed us to investigation the correction between the deformation and the precipitation over the Yangjiao region. After that, the slope angle and orientation angle derived from the DEM were employed to analyze their correlation with the slope deformation of the landslide. This analysis could help us better understand the geometry of land sliding direction and SAR deformation direction. Finally, the filed investigation was conducted to valid our observed slope deformation from L- and X-band SAR images.