Study On The Surface Vertical Deformation In The West Dongting Basin

The slowly, small scale surface deformation of Dongting basin in the plain area is mainly caused by dynamic geological process. After years of accumulation, this small scale deformation reached a certain variables, thus changing the local landscape, thereby affecting the environment and resulting a series of impact on the evolution of the Dongting Basin.This paper integrated GIS and RS technology to study the surface vertical deformation of the West Dongting Basin by using geological, seismic activity, remote sensing, and topographic data. First, the extent of the research area based on layers and watershed was determined, then the seismic activities in West Dongting basin were analyzed. The elevation information based on 1:5 ten thousand large scale topographic map was extracted and modeled in ArcGIS. After performing spatial analysis, surface vertical deformation rate of three representative figure of area were obtained and the reasons for such changes were analyzed.Finally, DInSAR technique is used to monitor the surface vertical deformation of Dongting Basin area. The three main conclusions are as follows:（1） Seismic activity in the West Dongting Basin is mainly due to several groups of fault activities. Frequent seismic activities provided evidence for the tectonic subsidence and uplift in West Dongting Basin.（2）Surface vertical deformation in three typical research area are controlled by the tectonic activity. Changde city is located at the junction of two secondary tectonic:Sun Mountain bulge and Changde Indentation units. Its southwest area experienced surface uplift, southeast area experienced sedimentation from the human activities area, and the area around Yuan river is lifted up, while other areas are subsidence. Jinshi city, in the other hand is located at junction of Sun Mountain and Lishui river fracture. Under the influence of both, while other area experienced surface lifting. The third city, HaoZixiang, is located in the eastern part of the study area, is affected by the tectonic subsidence movement thus most area is experiencing surface subsidence except for Datonghu which has a slight rise due to river sediment deposition.（3） Twenty two ASA_IMS₁P scenes of ENVISAT-1 satellite coverage of Hunan province were collected and organized according to acquisition time and parameters. Then using two-track DInSAR technique, the study of surface vertical deformation of Dongting Basin was performed. However, due to various factors, the experimental results could not accurately reflect the actual surface of vertical deformation.