President’s Postdoctoral Fellow
Department of Earth Sciences
The 2010 M7.0 Haiti earthquake was the first major earthquake in southern Haiti in 250 years. As this event could represent the beginning of a new period of active seismicity in the region, and in consideration of how vulnerable the population is to earthquake damage, it is important to understand the nature of this event and how it has influenced seismic hazards in the region. Most significantly, the 2010 earthquake occurred on the secondary Léogâne thrust fault (two fault segments), not the Enriquillo Fault, the major strike-slip fault in the region, despite it being only a few kilometers away. We first use a finite element model to simulate rupture along the Léogâne fault. We varied friction and background stress to investigate the conditions that best explain observed surface deformations and why the rupture did not to jump to the nearby Enriquillo fault. Our model successfully replicated rupture propagation along the two segments of the Léogâne fault, and indicated that a significant stress increase occurred on the top and to the west of the Enriquillo fault. We also investigated a 3D local tomography of this region. We considered 597 high-quality records from the earthquake catalog as recorded by temporary station deployments and simultaneously invert the travel times for hypocenter locations and 3D velocity structure in southern Haiti. Our results show a pronounced low velocity zone across the Léogâne fault, which is consistent with the sedimentary basin location from the geologic map. We also observe a southeast low velocity zone, which is consistent with a predefined structure in the morphology. This work provides information that can be used in future studies focusing on how changes in material properties can affect rupture propagation, which is useful to assess the seismic hazard that Haiti and other regions are facing.