Evidence of left-lateral active motion at the North America-Caribbean plate boundary

Wednesday, 17 December 2014
Sylvie D Leroy1, Nadine Ellouz2, Jordane Corbeau1, Frederique Rolandone1, B F Mercier De Lepinay3, Bertrand Meyer1, Roberte Momplaisir4, Jose-Luis Granja5, Anne Battani2, E B Burov1, Valerie Clouard6, Remy Deschamps2, Christian Gorini1, Youri Hamon2, Laetitia LE Pourhiet1, Nicolas Loget1, Francis Lucazeau7, Daniel Pillot2, Jeffrey Poort1, Kevin Tankoo8, Jose Luis Cuevas9, JoseFernando Alcaide9, Claude Jean Poix10, Serge Mitton11, Yamil Rodriguez12, Julien Schmitz2 and Alfonso Munoz Martin5, (1)Univ Paris 06 CNRS UMR7193, Sorbonne Univ. ISTEP, Paris, France, (2)IFP Energies nouvelles, Rueil-Malmaison Cedex, France, (3)GeoAzur, University of Nice-Sophia Antipolis, Valbonne, France, (4)UEH Haiti, Port-au-Prince, Haiti, (5)Complutense University of Madrid, Madrid, Spain, (6)Institut de Physique du Globe de Paris, Observatoire Volcanologique et Sismologique de la Martinique, Paris, France, (7)Institut de Physique du Globe, Paris, France, (8)UWI Mona Campus, Geography & Geology, Kingston, Jamaica, (9)CENAIS, Santiago de Cuba, Cuba, (10)Bureau des Mines Energie, Port-au-Prince, Haiti, (11)SEMANAH, PORT-AU-PRINCE, Haiti, (12)ANAMAR, Santo Domingo, Dominican Republic
The North America-Caribbean plate boundary is one of the least-known among large plate boundaries. Although it was identified early on as an example of a strike-slip fault in the north of Hispaniola, its structure and rate of motion remains poorly constrained. We present the first direct evidence for active sinistral strike-slip motion along this fault, based on swath seafloor mapping of the northern Haiti area. There is evidence for ~16.5 km of apparent strike-slip motion along the mapped segment of the Septentrional fault zone off Cap Haitien town which is terminated to the east onland Dominican republic and in the west to southern Cuban margin. By evaluating these new constraints within the context of geodetic models of global plate motions, we estimate an activity of the fault since 2 Ma with an angular velocity for the Caribbean plate relative to the North America predicted 6–12 mmyr1 sinistral motion along the Septentrional fault zone. This transform fault was initiated around 20 million years ago in its western segment and since 2 Ma in its eastern segment in response to a regional reorganization of plate velocities and directions, which induced a change in configuration of plate boundaries.