玛尼地震的InSAR形变研究与模拟

采用欧洲空间局ERS-2的星载干涉雷达数据,选取1997年11月8日MW7.6级玛尼地震作为研究对象,采用了差分干涉方法,在通过对覆盖同一地区的SAR数据进行差分干涉处理,得到了玛尼地震的视线向同震形变场。经研究发现:该地震形变场呈长轴近北东东向不规则椭圆形分布,地表破裂带长度约为130km,发震断层走向约为78°,断裂为左行走滑特征。断层以南为隆起区,在发震断层附近最大视线向隆起位移量为113.6cm,断层以北为沉降区,最大视线向沉降位移量为170.4cm。基于Okada模型实现了具有复杂结构的4段断层段参数的InSAR形变场数据模拟,获得断层的最大走滑为6m,估计出玛尼地震的标量地震矩M0为2.69×10^20Nm,计算得到的矩震级MW为7.6。证明了研究方法的正确性和研究结论的可靠性。

InSAR Deformation Research and Simulation of Mani Earthquake

By using the spaceborne Interferometric Radar Data of ESA ERS-2,taking the Mani MW7.6 earthquake on November 8th 1997 as the research object,the line-of-sight co-seismic deformation field of the Mani earthquake is obtained by using differential interferometric method to process the SAR data covering the same area.Results show that the seismic deformation field is irregular elliptical distribution along the long axis near NE and east direction,with a surface rupture zone length about 130 km,the strike of the seismogenic fault is about 78°,and the fault is characterized by left strike-slip.The south of the fault is the uplift area,has a maximum line-of-sight uplift displacement near the seismogenic fault as 113.6 cm,and the north of the fault is the subsidence area,has a maximum line-of-sight settlement displacement is 170.4 cm.Thanks to Okada model,the InSAR deformation field data of four fault segments with complex structure parameters are simulated,the maximum strike slip of the fault is got as 6 m,and the scalar seismic moment M0 of the Mani earthquake is estimated to be 2.69×10^20 Nm,and the moment magnitude MW is calculated as 7.6.All of the above results prove that the research methods are correct and research conclusions are reliable.