New Insights into Geohazard Risks in Jamaica, Haiti, and The Dominican Republic: A Compendium of Recent Geoscientists without Borders Results. Renee McDonald*, University of Southampton and Southern Methodist University; Vanshan Wright, Matthew J. Hornbach, Gwen Carris, Connor Flynn, Zach Frone, Joey Fontana, Emma Giddens, Austen Klausen. Brett Mattingly, Cliff Mauroner, and Benjamin Phrampus, Southern Methodist University; Lyndon Brown, University of the West Indies at Mona; Paul Mann, The University of Houston, and Cecilia McHugh, Queens College, New York. Summary The Greater Antilles islands of Jamaica and Hispanola experience infrequent but devastating earthquakes. Currently, it remains unclear (1) where active faults extend into western Jamaica and the western Dominican Republic, (2) what the probability of large (>Mw 7) earthquakes is in these island, and (3) what citizens can do to better prepare for such events. To begin addressing these questions, an interdisciplinary team of students and researcher, funded by SEG’s Geoscientists without Borders, conducted a 10 day geophysical study in Jamaica and a 7 day geophysical study in Haiti and the Dominican Republic during the winter and spring of 2013. The Jamaica study included a detailed factor-of-safety analysis in Kingston Harbor, with particular emphasis on the Palisadoes sand spit and Port Royal that are home to the Norman Manley International Airport, and Jamaican Defense Force Coast Guard Headquarters, respectively. Our preliminary analysis indicates an Mw 5 earthquake at the western end of the Enriquillo-Plantain Garden fault could trigger slope failure in unconsolidated sediments near Port Royal, with a magnitude 7 event almost certainly capable of generating slope failures at this site. Ongoing analysis of sediment cores collected in Kingston Harbor provides insight into the timing and probability of slope failure. At the time of this submission, we are just preparing for our field campaign in Hispanola that analyzes the location and timing of earthquakes in central part of the island and possible hydrogeologic links to lake flooding in the region. We will provide preliminary result from our Hispanola study at the 2013 SEG annual meeting. Introduction Jamaica, Haiti, and the Western Dominican Republic historically experience infrequent, but destructive earthquakes along the Enriquillo-Plantain Garden Fault (EPGF)--the same fault system that activated in 2010, killing nearly a quarter-million Haitians and devastating the capital city of Port-au-Prince. This fault system extends within a few kilometers of Jamaica’s capital city of Kingston, and was likely responsible for the 1692 and 1907 earthquakes in Jamaica that also destroyed much of the island (and like Haiti, resulted in complete destruction of Jamiaca’s commercial capital in 1692). The EPGF fault appears to extend into the western Dominican Republic, beneath Lake Enriquillo, however, the exact location (and rupture frequency) of the fault system in this region is poorly constrained. As a result, it remains unclear (1) where active components of this fault system extend into western Jamaica and the western Dominican Republic, (2) what the probability is of large (>Mw 7) earthquakes along the fault system, and (3) what citizens can do to better prepare for these events. To begin addressing these questions, an interdisciplinary team of students and researcher, funded by SEG’s Geoscientists without Borders conducted a 10 day geophysical study in Jamaica and a 7 day geophysical study in the Dominican Repubic/Haiti during the winter and spring of 2013. The study in Jamaica included 2D shallow water “chirp” seismic imaging, sediment coring, coastal slope surveying, and grain size analysis. We use these data to generate fault structure maps, and ultimately a detailed factor-of-safety analysis at key sites along the edge of Kingston Harbor. At the time of this writing, we are currently in the midst of prepare a geophysical field study of central Hispanola for May 2013 that includes coring and chirp seismic imaging in Lake Enriquillo in the Dominican Republic and Lake Sumatre, in Haiti. A primary goal of this study is locating and constraining the timing of large earthquakes in this region. Additionally, we will conduct temperature and salinity measurements across the lakes to address possible causes and sources of anomalous lake flooding at these sites. We will present our initial findings at the 2013 SEG annual meeting. PART I: Slope Failure Hazards in Kingston Harbour. Methods The seismic survey consisted of collecting 4.0kHz center- frequency chirp data on 16 NW-SE trending cross lines in Kingston Harbor, Jamaica. These data, combined with previous chirp data collected across the harbor in 2009 provide insight into the geologic structure beneath the harbor as well as the slope angle of unconsolidated sediment. We use these data in concert with sediment analysis to predict the earthquake magnitude necessary for slope failure and possible tsunami generation at the site. We sampled and analyzed beach sediments to obtain grain DOI http://dx.doi.org/10.1190/segam2013-1293.1 © 2013 SEG SEG Houston 2013 Annual Meeting Page 1234