Investigation of Focal Mechanism and Coseismic Slip Distribution for Haiti Mw 7.2 Earthquake in 2021

Objectives For investigating the crustal deformation and its focal mechanism caused by the 2021 Haiti Mw 7.2 earthquake, the coseismic deformation field of Haiti earthquake is obtained with differential interferometric synthetic aperture radar technology according to the ascending and descending orbit data provided by Sentinel-1A satellite.

Methods First, the observations are downsampled using uniform sampling methods. Then, fault parameters and optimal sliding distribution model are inversed using the Okada uniform elastic semi-infinite dislocation model. Finally, the displacements in three directions are calculated by the linear inversion data according to the forward model. The displacements in east, north, and up directions are projected to the line of sight(LOS) of the satellite, thereby acquiring the deformation field of the radar LOS in the experiment area.

Results The results show that this earthquake is a thrust and left-lateral strike-slip event. The optimal fault dip angle is determined 58°, the strike is 265.5°, and the slip angle is 50°. The epicenter location is 73.60°W,18.43°N, and the maximum sliding amount is 3.2 m.

Conclusions The deformation of the earthquake is mainly uplift, and its value is 64 cm, which is the result of the combined action of the main shock and aftershocks.