The 2010 Haiti earthquake: A complex fault pattern constrained by seismologic and tectonic observations

Type Article
Date 2011-11
Language English
Author(s) de Lepinay Bernard Mercier1, Deschamps Anne1, Klingelhoefer FraukeORCID2, Mazabraud Yves3, Delouis Bertrand1, Clouard Valerie4, Hello Yann1, Crozon Jacques2, Marcaillou Boris3, Graindorge David5, Vallee Martin1, Perrot Julie5, Bouin Marie-Paule6, Saurel Jean-Marie4, Charvis Philippe1, St-Louis Mildor7
Affiliation(s) 1 : Univ Nice, CNRS, IRD, F-06560 Valbonne, France.
2 : IFREMER, F-29280 Plouzane, France.
3 : Univ Antilles Guyane, IUFM Guadeloupe, Pointe A Pitre 97159, Guadeloupe.
4 : Inst Phys Globe, Observ Volcanol & Sismol Martin, Fonds St Denis 97250, Martinique.
5 : Univ Bretagne Occidentale, IUEM, F-29280 Plouzane, France.
6 : Inst Phys Globe, Observ Volcanol & Sismol Guadeloupe, Gourbeyre 97113, Guadeloupe.
7 : Bur Mines & Energie, Port Au Prince, Haiti.
Source Geophysical Research Letters (0094-8276) (Amer Geophysical Union), 2011-11 , Vol. 38 , N. L22305 , P. 7 p.
DOI 10.1029/2011GL049799
WOS© Times Cited 39
Abstract 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: the rupture occurred on a wrench fault at the rheologic boundary on top of the under-thrusting rigid oceanic block, whereas the aftershocks were the result of the relaxation on the hanging wall along pre-existing discontinuities in the frontal part of the Transhaitian Belt. Citation: Mercier de Lepinay, B., et al. (2011), The 2010 Haiti earthquake: A complex fault pattern constrained by seismologic and tectonic observations, Geophys. Res. Lett., 38, L22305, doi:10.1029/2011GL049799.
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de Lepinay Bernard Mercier, Deschamps Anne, Klingelhoefer Frauke, Mazabraud Yves, Delouis Bertrand, Clouard Valerie, Hello Yann, Crozon Jacques, Marcaillou Boris, Graindorge David, Vallee Martin, Perrot Julie, Bouin Marie-Paule, Saurel Jean-Marie, Charvis Philippe, St-Louis Mildor (2011). The 2010 Haiti earthquake: A complex fault pattern constrained by seismologic and tectonic observations. Geophysical Research Letters, 38(L22305), 7 p. Publisher's official version : , Open Access version :