The 2010 Haiti earthquake : a complex fault pattern constrained by seismologic and tectonic observations Mercier de Lépinay, B. Deschamps, A. Klingelhoefer, F. Mazabraud, Y. Delouis, B. Clouard, V. /Hello, Yann Crozon, J. Marcaillou, B. Graindorge, D. /Vallée, Martin Perrot, J. Bouin, M. P. Saurel, J. M. /Charvis, Philippe St-Louis, M. After the January 12, 2010, Haiti earthquake, we deployed a mainly offshore temporary network of seismologic stations around the damaged area. The distribution of the recorded aftershocks, together with morphotectonic observations and mainshock analysis, allow us to constrain a complex fault pattern in the area. Almost all of the aftershocks have a N-S compressive mechanism, and not the expected left-lateral strike-slip mechanism. A first-order slip model of the mainshock shows a N264 degrees E north-dipping plane, with a major left-lateral component and a strong reverse component. As the aftershock distribution is sub-parallel and close to the Enriquillo fault, we assume that although the cause of the catastrophe was not a rupture along the Enriquillo fault, this fault had an important role as a mechanical boundary. The azimuth of the focal planes of the aftershocks are parallel to the north-dipping faults of the Transhaitian Belt, which suggests a triggering of failure on these discontinuities. In the western part, the aftershock distribution reflects the triggering of slip on similar faults, and/or, alternatively, of the south-dipping faults, such the Trois-Baies submarine fault. These observations are in agreement with a model of an oblique collision of an indenter of the oceanic crust of the Southern Peninsula and the sedimentary wedge of the Transhaitian Belt. 2011 text https://www.documentation.ird.fr/hor/fdi:010054243 fdi:010054243 Mercier de Lépinay B., Deschamps A., Klingelhoefer F., Mazabraud Y., Delouis B., Clouard V., Hello Yann, Crozon J., Marcaillou B., Graindorge D., Vallée Martin, Perrot J., Bouin M. P., Saurel J. M., Charvis Philippe, St-Louis M.. The 2010 Haiti earthquake : a complex fault pattern constrained by seismologic and tectonic observations. 2011, 38, L22305 EN