2020年土耳其MW5.7地震InSAR同震形变特征与破裂滑动分布

为准确认识2020-06-14土耳其MW5.7地震的发震位置、构造特点以及地震危险性，利用D-InSAR技术对Sentinel-1A数据进行处理，基于GACOS进行大气校正，获得视线向（line of sight，LOS）同震形变场。降轨LOS向同震形变场显示，断层北侧抬升，最大抬升形变量约8.87 cm；南侧沉降，最大沉降量约-7.75 cm。以LOS向同震形变为约束，先采用贝叶斯自举优化法反演发震断层几何参数，然后使用有限断层方法反演地震破裂滑动分布。结果显示，断层走向约257.48°±0.65°、倾角约79.69°±0.98°、滑动角约154.2°±3.8°，震中位置为（40.754°E，39.389°N），破裂区域长度约8 km、宽度约6 km，破裂的最浅埋深约0.8 km、最大埋深约8.9 km，最大滑动量约0.57 m，对应深度约4.278 km。地震释放地震矩约4.54×1017 Nm，对应矩震级MW5.7，与土耳其灾害和紧急情况管理局公布的结果一致。此次土耳其地震受近东西向的潜伏断层控制，以右旋走滑为主兼具少量的逆冲特性。地震造成部分地区的库伦破裂应力增量超过0.1 bar，这些区域未来的地震危险性值得关注。

Coseismic Deformation Field of the 2020 Turkey Mw5.7 Earthquake from Sentinel-1A InSAR Data and Rupture Slip Distribution

We analyze the location andtectonic characteristics of the June 14, 2020 MW5.7 earthquake that occurred in Turkey, evaluating the seismic hazards. In this paper, we use D-InSAR technology to process the Sentinel-1A SAR data and GACOS is used for atmospheric correction to obtain line of sight coseismic deformation field. The LOS coseismic deformation field of descending track shows that the uplift on the north side and the subsidence on the south side of the fault. The maximum subsidence is about -7.75 cm and the maximum uplift value is about 8.87 cm. Constrained by LOS coseismic deformation, first we obtain the geometric parameters of the seismic fault are by Bayesian bootstrap optimization (BABO) method, and then the seismic rupture slip distribution is obtained by finite fault method.The inversion shows that the strike is about 257.48°±0.65°, the dip is about 79.69°±0.98°, the rake is about 154.2°±3.8°, the epicenter is (40.754°E,39.389°N). The length and width of the main rupture region are about 8 km×6 km, the shallowest buried depth is about 0.8 km, the deepest buried depth is about 8.9 km. The maximum slip on the fault is 0.57 m at the depth of 4.278 km. The seismic moment is about 4.54×1017 Nm (MW5.7), which agrees with the results published by the Turkey’s Disaster & Emergency Management Authority.The Turkey earthquake is controlled by a near EW blind fault and is mainly a dextral strike-slip with minor thrust. The earthquake caused the Coulomb failure stress to increase by more than 0.1 bar in some areas, and the future risk of these areas deserves more attention.