Focal Mechanism Inversion and 3D Deformation Field Acquisition of Iran Mw7.3 Earthquake in 2017

On November 12, 2017, a strong Mw7.3 earthquake occurred in the Sarpol-e Zahab region on the Iranian-Iraqi border, killing more than 500 people. Earthquakes cause serious damage, but do not cause rupture of seismogenic faults on the earth's surface. In order to study the focal mechanism of earthquakes and the crustal deformation caused by earthquakes, this paper uses ALOS-2 and Sentinel-1 satellite data, obtains the seismic co-seismic deformation field by over-differential interferometry, and then uses the resolution constrained quadtree sampling method to observe it. The data are sampled for down sampling. On this basis, a two-step inversion algorithm is used to subdivide the fault plane, and the precise geometric parameters and the optimal fault slip distribution are obtained by inversion. The inversion results show that the seismogenic fault is a fault with thrust and dextral strike slip, and the fault strike is determined 347°. The inclination angle is 15°. The distribution of seismic slip is mainly distributed in16-19 km. The depth range and the maximum tilting slip are 4.5 m. Based on the inversion of the fault model, the 3D seismic deformation field is obtained. The results of the 3D seismic deformation field show that the deformation caused by the earthquake is mainly in the vertical direction, and the vertical uplift deformation reaches 78.8 cm. The inversion results of the focal mechanism and the three-dimensional deformation field results are in good agreement with the seismological research results.