Monitoring Ground Deformation In Urban And Mining Area Using PS-DInSAR Technology

Land subsidence has become a major type of geological disaster.It has already caused serious threats to people's lives and property safety.Therefore,in order to prevent and reduce this disaster,it is significant to obtain efficiently deformation information.Spaceborne Synthetic Aperture Radar Interferometry as a new potential remote sensing technology at present,and its differential interferometry has advantages of wide range,all-time,high precision and high spatial resolution to monitor land subsidence.However,its practical application is seriously restricted due to the spatio-temporal decorrelation and atmospheric delay phase.In recent years,a time-series Persistent Scatterer Differential Interferometric Synthetic Aperture technology(PS-DInSAR)has been proposed by some scholars in the world,which overcomes the problems of spatio-temporal decorrelation and atmospheric delay.PS-DInSAR technology was used to monitor the land subsidence of the Xuangang mining area and Taiyuan City in this paper.The twenty scenes Sentinel-1A images of Taiyuan City were processed by PS-DInSAR technology.And the average annual deformation rate,cumulative time series land subsidence and cumulative subsidence area of Taiyuan City during February the 17 th,2016 to February the 18 th,2018 were obtained by PS-DInSAR.According to analysis,it can be showed that:(1)The subsidence area of Taiyuan City was mainly distributed in Xizhang,Wujiabao,Xiaodian,Beigunian and the east of Yangjiayu during February the 17 th,2016 to February the 18 th,2018.Xiaodian was the largest subsidence area whose average annual subsidence rate is-40mm/y to-80mm/y.(2)Taking February the 17 th,2016 as time reference,a trend of subsidence was showed in most areas before May 6th,2017 and started to alleviate after May 6th,2017 in Taiyuan City.With the continuous development of Xiaodian high-tech zone,the cumulative subsidence was 60 mm to 120 mm on February the 18 th,2018,and the land subsidence in this area will be affected by the Tianzhuang fault.In addition,the cumulative subsidence of the Xizhang subsidence center reached 20mm-60 mm.(3)With time passing,the cumulative subsidence area in Taiyuan City increased continuously.Only after June 11 th,2017 the area of cumulative subsidence of more than 0.02 m showed a downtrend.By analyzing the relationship between the distribution of wells and average annual deformation rate,it showed that they are highly correlated.The overall surface deformation of Taiyuan city can be obtained with sufficient PS point.The twenty-six scenes Sentinel-1A images of Xuangang mining area were processed by PS-DInSAR technology.And the average annual deformation rate,cumulative time series land subsidence and cumulative subsidence area of Xuangang mining area during November 13 th,2015 to May 30 th,2017 were obtained by PS-DInSAR.The results indicate that:(1)The average annual subsidence rate of Xuangang mining area ranged from-23mm/y to 26mm/y.In addition,the subsidence area was mainly distributed in the east and south of Xuangang mining area and near Ningwu County,and the subsidence rate ranged from-5mm/y to-15mm/y in most areas.And there were two obvious subsidence funnels at Liujialiang minefield and Jiaojiazhai minefield.(2)Taking November 13 th,2015 as time reference,cumulative subsidence of Liujialiang minefield?Jiaojiazhai minefield and Ningwu County was increased continuously.cumulative subsidence of many subsidence areas was 20 mm to 40 mm.(3)With time passing,the cumulative subsidence area of Xuangang mining area was continuously expanding.Finally,the correlation between them was high by analyzing the relationship between the distribution of coal mine and average annual deformation rate of acquired PS point.PS points were not available in many subsidence areas of Xuangang mining area that were covered by vegetation.As a result,the subsidence of the mines is smaller than that of the urban.In this study,Taiyuan city and Xuangang mining area were selected as the study area,and the land subsidence of Taiyuan city during February the 17 th,2016 to February the 18 th,2018 and Xuangang mining area during November 13 th,2015 to May 30 th,2017 was monitored by PS-DInSAR technology.The surface deformation characteristics of the Xuangang mining area and Taiyuan City were obtained.And the surface deformation characteristics were analyzed from three aspects:average annual deformation rate,cumulative time series land subsidence and cumulative subsidence area.The distribution of wells and coal mine agreed well with subsidence areas of acquired PS points.Sufficient PS points can be obtained in city by PS-DInSAR technology,while PS points were few in mining area that was covered by vegetation.Therefore,from the perspective of PS points distribution,PS-DInSAR technology is more suitable for monitoring city land subsidence.