Coseismic and Early Postseismic Slip of the 2021 Mw 7.2 Nippes, Haiti, Earthquake: Transpressional Rupture of a Nonplanar Dipping Fault System

Abstract

Abstract On 14 August 2021, an Mw 7.2 earthquake struck Nippes, Haiti, 11 yr after the devastating 2010 Mw 7.0 Port-au-Prince earthquake. This earthquake occurred in a remote region where the structure at the depth of the main boundary Enriquillo Plantain Garden fault (EPGF) is less known. Using Synthetic Aperture Radar imagery, we retrieve the coseismic and early postseismic deformation of the 2021 Haiti earthquake to constrain its fault geometry and slip distribution. Our modeling results show that the 2021 earthquake ruptured the high-angle Ravine du Sud fault and a bend fault ∼64° dipping to the north at depth. Although not only conclusive, the combination of coseismic and postseismic deformation, along with geomorphic features, and relocated aftershocks, suggest a nonplanar fault structure with significant variations in dip angles along both the depth and track of the EPGF in this region. East of the epicenter, we document a 25 km section along the EPGF that crept for ∼15 days. This distribution of aseismic slip utilizing stacked deformation indicates that only a small fraction of the accumulated strain near the surface was released during the earthquake, suggesting a high potential for seismic hazard in the region along the EPGF from the ruptured segment to the east, before reaching the 2010 rupture.