基于D-InSAR的长宁地震形变场提取与模拟

2019年6月19日四川长宁县发生Ms6.0地震，提取地震同震形变场，反演震源机制，对于地震破裂分析、指导救灾具有重要意义。本文利用两轨差分干涉处理覆盖长宁地震影响区域的两景Sentinel-1A影像，在对D-InSAR关键技术和影像特征研究的基础上，配置处理方法和参数，提取了此次地震的同震形变场，采用Okada模型和正向建模对发震断层的几何参数及形变场进行了反演和模拟。结果表明，长宁地震形变场呈西北—东南走向的次级断层控制的不规则椭圆形，断层的两侧区域特征差异明显，断层左下侧为沉降区，右上侧为隆升区，两者的最大视线向形变分别为8、6 cm。断层的运动主要以左旋走滑为主，平均滑动距离约0.38 m，平均滑动角约55°，正向模拟的形变场与观测结果相符，这表明观测结果较可靠，同时也提高了低相干形变区的观测精度。

Deformation field extraction and simulation of Changning earthquake based on D-InSAR

On June 19, 2019, the Ms6.0 earthquake occurred in Changning County, Sichuan Province. The seismic coseismic deformation field was extracted and the focal mechanism was inverted. It is of great significance for the analysis of earthquake rupture and guiding disaster relief. Two-track differential interference processing is used to cover the two scenes of Sentinel-1A image in the area affected by Changning earthquake. Based on the research on key technologies and image features of D-InSAR, the processing methods and parameters are configured to extract the coseismic deformation field of the earthquake. The Okada model and forward modeling are used to invert and simulate the geometric parameters and deformation fields of the seismogenic fault. The results show that the deformation field of Changning earthquake is irregular elliptical shape controlled by the northwest-oriented secondary fault. The characteristics of the two sides of the fault are obviously different. The lower left side of the fault is the subsidence area, and the upper right side is the uplift area. The maximum line of sight of the two is the maximum line of sight. The deformation is 8 and 6 cm, respectively. The motion of the fault is mainly left-lateral strike-slip, the average sliding distance is about 0.38 m, and the average sliding angle is about 55°. The positive simulated deformation field is consistent with the observation results, which proves that the observation results are more reliable and improve the observation accuracy of the low coherence deformation zone.