基于InSAR技术的张家口定点形变观测场地形变监测

Deformation Detection and Analysis of Fixed Point Deformation Observation at Zhangjiakou Based on InSAR Technology

针对张家口定点形变观测场地伸缩仪NS向观测曲线在2020年6月至12月出现加速上升的异常变化,以张家口定点形变观测场地为研究区域,基于Sentinel-1 SAR降轨数据并采用小基线集技术对场地进行形变监测,并获取了2018—2020年该区垂向年平均形变速率和形变时间序列。研究结果表明:张家口断裂两侧地表在垂向的相对运动速率小于1 mm/a,断层活动性较弱;张家口断裂在NNW-SSE向拉张应力作用下,使得断层南盘地表相对北盘出现较为明显的沉降运动,导致张家口伸缩仪NS向观测出现张性加速趋势变化异常现象。

The NS direction of tensometer of Zhangjiakou fixed-point deformation observation site has accelerated rising anomaly from June to December 2020.In view of this anomaly,we take Zhangjiakou fixed-point deformation observation site as the research area,based on sentinel-1 SAR descending imaging and small baseline subset(SBAS)technology for InSAR time series analysis.we obtains the vertical annual average deformation rate and deformation time series in this area from 2018 to 2020.The results show that the vertical relative movement rate of the surface on both sides of Zhangjiakou fault is less than 1 mm/a,and the fault activity is weak.Under the action of NNW-SSE tensile stress,the southern side surface of Zhangjiakou fault appears obvious subsidence movement relative to the northern side,this is the reason why the observation curves of the NS component of tensometer in Zhangjiakou seismic station showed the abnormal change of tensile acceleration trend.