Dizhi lixue xuebao (Apr 2022)
Analysis on the development law of active geological hazards in the Loess Plateau based on InSAR identification
Abstract
Active geological disasters induced by earthquakes, rainfalls and human engineering activities occur frequently in the Loess Plateau. However, there is a lack of systematic understanding of the development and distribution of active geological disasters in the Loess Plateau due to the wide area, active structure, diverse landforms and great difference in loess characteristics. InSAR technology can observe surface deformation in a wide range. Based on 40 sentinal-1 SAR data from January 1, 2019 to March 31, 2020, a total of 3286 active geological disasters in the Loess Plateau of 624, 600 km2 were interpreted by InSAR, including 1135 landslides, 1691 mining collapses, 368 subsidences and 92 landfills. Combined with geomorphological and optical image characteristics, four types of active geological hazards were interpreted, which reveals that they are mainly distributed in eight regions, including four landslide areas, three mining collapse areas and one subsidence area. The spatial distribution of active landslides is obviously regional and clustered, concentrating in the middle and west of China; while that of mining collapse and land subsidence densely developed in groups in the middle and west of China. There is a relationship between landslide development density and topography. The development of these geological disasters has an obvious spatio-temporal regularity. Regionally, the development intensity of geological disasters is controlled by topography and mineral resources; and in terms of scale, disasters identified by InSAR are all above medium size, which is different from traditional statistical methods. InSAR identification results objectively reflect the distribution of geological disasters in the Loess Plateau, and deepened our understanding on that as well. InSAR technique, meanwhile, can effectively detect the surface damage induced by underground coal mining, including its distribution, scope, strength, and monitor the depth and scope of opencast coal mine, and then infer the intensity of coal production activities.
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