The 2010 Haiti earthquake: A complex fault pattern constrained by seismologic and tectonic observations
|Author(s)||de Lepinay Bernard Mercier1, Deschamps Anne1, Klingelhoefer Frauke2, 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.|
|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.|