1 SCIENTIFIC REPORT SEIS-UK loan 987 “Trans-Haiti: Crustal-scale geodynamics of the Hispaniola plate boundary in the Caribbean” (April 2013- June 2014) Frédérique Rolandone 1 , Sylvie Leroy 1 , Derek Keir 2 , Graham Stuart 3 1 ISTEP, UPMC CNRS, Univ. Paris 6, Paris, France 2 National Oceanography Centre Southampton, University of Southampton 3 School of Earth and Environment, University of Leeds, Leeds, LS2 9JT Abstract SEIS-UK provided a loan of 23 broadband seismic systems (11 40TD and 12 6TD) for deployment in Haiti, from April 2013 until June 2014. The University Paris VI provided an additional 4 Reftek- 40T broadband seismic stations deployed for the same period of time. These systems recorded continuously at 100 samples per second, with relatively minor data losses due to equipment problems. The dataset collected has been archived via SEIS-UK with IRIS (Incorporated Research Institutions for Seismology). Records of teleseisms have been processed and receiver functions have been computed to reveal the structure of the crust as part of a PhD study in Paris VI University by Jordane Corbeau. Further processing for surface wave tomography using fast anisotropy directions obtained from SKS wave arrivals to reveal the signature of lithospheric deformation will be performed during a NERC oil and gas cdt funded PhD at the University of Southampton. Local earthquakes were also recorded during the TRANS-HAITI project and the location of the microseismicity is still in progress. In addition, SEIS-UK provided a loan of 10 geophones in November 2013 for a short active source experiment. Background Following the destructive 2010 Mw 7.0 Haiti earthquake, an international effort was initiated to investigate the corresponding active fault system and to better understand the crustal and upper mantle structure beneath Haiti. The Caribbean plate is currently moving eastward relative to North America and the plate motion is accommodated along a complex, 200 km-wide deformed zone, the Northern Caribbean plate Boundary. The Northern Caribbean plate Boundary is a seismogenic zone extending over 3000 km along the northern edge of the Caribbean Sea and a deforming region that includes two large strike-slip fault systems, the Septentrional-Oriente fault zone (SOFZ) in the north and the Enriquillo-Plantain-Garden fault zone (EPGFZ) in the south (Mann et al., 1995; Fig. 1). Despite the importance of the 2010 Haiti earthquake, we know relatively little about the structure and large-scale geodynamics of this transpressional fault zone. The goals of the TRANS-HAITI project are to use both local earthquake and teleseismic techniques to image the variation in fault architecture and lithospheric structure across the plate boundary in Haiti. Survey procedure The 23 seismometers loaned from SEIS-UK and the 4 French stations were deployed for a year in Haiti from April 2013 until June 2014. 19 stations were deployed along a roughly north-south profile in Haiti (in red in Fig. 2), with the objective of investigating the structure of the crust and the lithosphere. 7 stations were deployed outside this profile (in blue in Fig. 2) to complement the station distribution in order to record the seismicity with magnitude of approximately 3 and above.