HR: 16:30h
AN: T14B-03    [Abstracts]
TI: High resolution 3D laser scanner measurements of a strike-slip fault
AU: Marsan, D
EM: david.marsan@univ-savoie.fr
AF: LGIT, Universit‚ de Savoie, LGIT, Universit‚ de Savoie, Le Bourget du Lac, 73376 France
AU: * Renard, F
EM: francois.renard@ujf-grenoble.fr
AF: LGIT, Universit‚ de Grenoble, BP 53, Grenoble, FRA 38041
AU: Voisin, C
EM: christophe.voisin@ujf-grenoble.fr
AF: LGIT, Universit‚ de Grenoble, BP 53, Grenoble, FRA 38041
AU: Schmittbuhl, J
EM: jean.schmittbuhl@eost.u-strasbg.fr
AF: Institut de Physique du Globe de Strasbourg, 5 rue Ren‚ Descartes, Strasbourg, 67084 France
AB: The roughness on active fault planes is supposed to concentrate the stress along asperities and therefore control earthquakes nucleation. Unfortunately, the small scale roughness cannot be imaged for faults at depth because of the lack of resolution of earthquakes relocalization methods. The surface roughness of a recently exhumed strike-slip fault in the Alps has been measured by three independent 3D portable laser scanners. Digital elevation models of several fault surface areas, from 1 m2 to 600 m2, have been measured at a resolution ranging from 5 mm to 80 mm. Statistical scaling analyses show that the striated fault surface has a directional morphological anisotropy that can be described by two scaling roughness exponents, in two directions corresponding to the direction of slip and its perpendicular. A crossover length at the centimeter scale emerges from the two scaling regimes indicating that the anisotropy of the fault roughness should control the rupture propagation differently below and above this length scale.
DE: 7209 Earthquake dynamics (1242)
DE: 8118 Dynamics and mechanics of faulting (8004)
SC: Tectonophysics [T]
MN: Fall Meeting 2005