山西清徐地裂缝形变的InSAR监测分析

山西清徐地裂缝是近年汾渭盆地中活动最为剧烈的地裂缝之一,对耕地、道路和建筑物均造成了严重的破坏。为了监测该地裂缝的活动特征并推测其活动原因,采用差分合成孔径雷达干涉测量技术对该区域的地表形变进行了面状监测。由于受农田覆盖导致的严重时间去相干的影响,本文采用2007年时隔仅为70d的两景Envisat ASAR数据进行了解算,获取了该时间段清徐地区的整体地表形变,特别是清徐地裂缝两侧的形变梯度信息。结果显示: 清徐地裂缝南侧有一个长轴约为2km的地面沉降区域。进一步通过两条平行于地裂缝的剖线和多条垂直于地裂缝的剖线对该地裂缝形变的空间特征进行了分析,结果显示: 清徐地裂缝南侧为主要的形变区域,地裂缝最大的影响宽度达100m,而且地裂缝的不同地段的活动强度也不同, 70d的最大差异形变达5cm。从地裂缝与断裂的空间来看,该地裂缝位置受到交城断裂的控制,而推测近年地裂缝的异常活动则源于地裂缝南侧沉降中心的出现。

DEFORMATION MONITORING OF GROUND FISSURE WITH SAR INTERFEROMETRY IN QINGXU,SHANXI PROVINCE

Recently,as investigated,the ground fissure in Qingxu of Shanxi province is one of the most active fissures in Fenwei Basin. It has caused serious damages to surface infrastructures such as roads and buildings.In order to monitor the deformation of the Qingxu fissure and to deduce its cause,this paper uses the differential SAR interferometry technique(D-InSAR).In order to mitigate the temporal decorrelation over the farm region, two scenes of Envisat ASAR data with only 70 days intervals in 2007 are selected and used to generated surface deformation results.Firstly, a subsidence of cone shape is detected as an ellipsoid with 2km long axis located in the south of Qingxu fissure. Then two profiles paralleling to the fissure and eight profiles normal to the fissure are taken to analyze the spatial characteristics of the fissure. It is found that the main deformation area is located in the south of the fissure. The maximum influence width is up to 100 m. Besides, it is found that the activity of ground fissure in different areas is greatly different. The maximum land subsidence difference crossing the ground fissure is up to 5 cm. Finally, the Jiaocheng fault is deduced to control the location of Qingxu fissure. The great land subsidence is the main sake for unusual activity of Qingxu fissure.