Oblique Convergence Causes Both Thrust and Strike-Slip Ruptures During the 2021 M 7.2 Haiti Earthquake

A devastating magnitude 7.2 earthquake struck Southern Haiti on 14 August 2021. The earthquake caused severe damage and over 2000 casualties. Resolving the earthquake rupture process can provide critical insights into hazard mitigation. Here we use integrated seismological analyses to obtain the rupture history of the 2021 earthquake. We find the earthquake first broke a blind thrust fault and then jumped to a disconnected strike-slip fault. Neither of the fault configurations aligns with the left-lateral tectonic boundary between the Caribbean and North American plates. The complex multi-fault rupture may result from the oblique plate convergence in the region, so that the initial thrust rupture is due to the boundary-normal compression and the following strike-slip faulting originates from the Gonave microplate block movement, orienting SW-NE direction. The complex rupture development of the earthquake suggests that the regional deformation is accommodated by a network of segmented faults with diverse faulting conditions.

Automated summary

On August 14, 2021, a devastating magnitude 7.2 earthquake struck Southern Haiti, causing severe damage and over 2000 casualties. Integrated seismological analyses revealed that the earthquake first ruptured a blind thrust fault and then propagated to a disconnected strike-slip fault. The complex rupture process suggests that the regional deformation is accommodated by a network of segmented faults with diverse faulting conditions.