Study On The Application Of InSAR Technique In Monitoring Ground Subsidence

Ground subsidence has become one of the main geological hazards that bring environmental problems and limit the sustainable development of social economy. Interferometric synthetic aperture radar technique is a new and effective method for monitering ground subsidence, and it has many advantages compared with the traditional technologies. So it has become one of the hot fields in the world. But spatial decorrelation, temporal decorrelation and atmospheric effect, not only affect the reliability and accuracy of monitoring land subsidence, but also limit the practical application of InSAR technique. Aiming at the application requirements of a new method for monitering ground subsidence, according to different characteristics of ground subsidence, the application of InSAR technique in monitoring mining area ground subsidence and monitoring urban ground subsidence were systematically studied.The main research work and contributions of this paper were as follows:(1)It had sdudied the basic principle of InSAR technique systematically. Especially, the basic principles of D-InSAR, PS-InSAR and SBAS-InSAR applied to moniter ground subsidence were introduced. By analyzing and summarizing the limitations of different InSAR technique methods, it got the applicability of different InSAR technique methods for monitoring different land subsidence.(2)The application of two-pass D-InSAR technique in monitoring ground subsidence in the coal mining area was studied. It selected YanZhou coal mining area as test area. We used 14 ALOS PALSAR images from 2007 to 2010 to detect the subsided areas and got the vertical subsided quantity by two-pass D-InSAR technique. Selecting interferometric pairs and forming data processing flow of two-pass D-InSAR technique which is suitable for monitoring ground subsidence in the coal mining area. We got the subsidence field map of these interferometric pairs, then, we made a detailed analysis and interpretation of several important subsided areas upon coal face. And it generated the 3-D deformation map, the isoline map and profiles of land subsidence for facilitating to interpret the deformation fields. At last, we analyzed the deformation trends of seven typical subsidence fields. By comparing of the monitoring results of D-InSAR and Leveling, it carried out the accuracy verification and analysis for InSAR measuring. And we found that the vertical displacement got by D-InSAR technique was consistent with the leveling results. The test indicated that two-pass D-InSAR technique based on L-band PALSAR data and SRTM DEM is a very simple, rapid and efficient way in detecting and monitoring ground subsidence in the coal mining area, even in areas with vegetation covered. So it is one of the best choices for monitoring large scale coal mining area ground subsidence.(3)The application of InSAR time series analysis methods in monitoring urban ground subsidence was studied. It selected Beijing district as test area. We use 19 ENVISAT ASAR images from 2003 to 2007 to derive LOS deformation by InSAR time series analysis methods. It selected common master image according to some rules which have the smallest sum of absolute value of spatial perpendicular baselines, temperal baselines and Doppler centers frequency baselines. Through estimating and subtracting all kinds of errors, we derived the ground subsidence information of Beijing area by PS-InSAR, SBAS-InSAR and MT-InSAR methods, including the mean los velocity and the deformation time series. By the analyzing of these deformation results derived from these methods accord to the facts of Beijing ground subsidence, we found that the main deformation trend derived from these methods are consistent with the facts. The experiment proved that the InSAR time series analysis methods are suitable for monitoring long-time, large-area and slowly deformation, such as the urban land subsidence. It is particularly suited for the assessment of the impact of subsidence.