RAPID: Collaborative Research: Off-shore coseismic effects of the Port au Prince earthquake, Haiti

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In the aftermath of the catastrophic M7 earthquake in Haiti there is an urgent need to record aftershocks and capture ephemeral data that will help to assess both short term (immediate) and long term earthquake risk in the region. Reliable models of strain accumulation and seismogenic release along the fault zone are urgently needed. A U.S. team is already on the ground, installing additional seismometers and GPS stations and mapping features associated with the earthquake, and a French team is preparing to deploy a suite of ocean bottom seismometers offshore. The January 12 mainshock ruptured a relatively small segment of the Enriquillo-Plantain Garden fault zone (EPGF), the southern of two parallel E-W sinistral transforms accommodating most of the motion between the North America and Caribbean plates. The EPGF follows the core of the southern peninsula and is associated with several large historic earthquakes, but its pre-1700?s paleoseismicity is unknown. A number of NW-SE faults and folds intersect the EPGF and may also be active. Many of these structures are unmapped, especially offshore, including a possible one in the Baie de Port au Prince. This survey of the offshore portion of the main rupture and of some of the secondary structures associated with it along the southern peninsula and the Baie de Port au Prince will complement those efforts by documenting the near surface effects of the earthquake offshore and characterizing the seismogenic structures. The survey will include shallow water (300 m) multibeam mapping, with coincident and targeted sidescan sonar, and chirp (0.5-12 kHz) sonar profiles, and spot coring. The principal broader impact of this study is its very high and immediate societal relevance.