Roby Douilly, UC Riverside, Crustal Structure Investigation Following the 2010 Haiti Earthquake

GEOPHYSICS DEPARTMENT SEMINAR

Roby Douilly

Department of Earth and Planetary Sciences, University of California, Riverside

Crustal Structure Investigation Following the 2010 Haiti Earthquake

Date: Thursday, January 23, 2020

Location: Mitchell 350/372

Time: 12:00 pm - 1:15 pm

Host: William Ellsworth

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, geodetic data showed that the 2010 earthquake occurred on the secondary Léogâne thrust fault (two fault segments), not the Enriquillo Plantain Garden fault (EPGF), the major strike-slip fault in the region, despite it being only a few kilometers away. Following the earthquake, several groups had installed temporary seismic stations to record aftershocks and we used this combined dataset to clearly delineate the Léogâne fault, with a geometry close to that inferred from geodetic data. The aftershocks also delineate a structure with shallower southward dip offshore and to the west of the rupture zone, which could indicate triggered seismicity on the offshore Trois Baies reverse fault (TBF). Using this dataset, we also investigated a detailed 3D crustal structure of this region. In addition, we used a finite element model to simulate scenarios of the 2010 Haiti earthquake to understand why the rupture did not jump to the nearby Enriquillo fault. These work provide 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 is currently facing.