La fédération
Intranet
Projet SUBDUCTION : standard and slow seismology
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Durée : 2012 - 2014
Coordinateur : Jean Virieux (ISTerre)
Equipe ISterre impliquée :
– Onde et structure
Collaborations :
– BRGM
– LSPM
– Laboratoire de géologie de ENS
)]
« How do earthquakes slip » is one of the “Grand challenges in seismology” published by American seismologists two years ago (http://www.iris.edu/hp/lrsps/seis_plan_final.pdf). We shall take the unique opportunity of recent earthquakes in subduction zones as well as the now existing computer capabilities of simulations for an improved understanding of this complex non-linear physics where slip occurs as plates are loaded by stresses in the lithosphere and resisted by frictional forces on faults.
Events in Chili subduction zone with the major aftershock 16 December 2007 of the 14 November 2007 main shock in Tocopilla as well as the new Mw 8.8 Maule earthquake of 27 February 2010 will be analyzed through dynamic rupture inversion of accelerograms and cGPS while slow slip events in the Guerrero section of the Mexican subduction which has occurred in 2002, 2006 and 2010 will be investigated through kinematic rupture inversion using more than 15 GPS stations as well as InSAR data as well as a two-steps inversion for dynamic parameters inference.
These analyses will motivate improved rupture modeling considering more realistic fault geometries and fault cohesion when necessary. Local precision for rupture while retaining propagation properties inside the while subduction zone for dynamic loading is the challenge. Through numerical investigations, we shall address the importance of these input parameters as well as the critical initial loading in the nucleation process which is one difficult theoretical breakthrough we want to face. Related results will give us confidence in our inversion results or will motivate us for the introduction of these new modeling capabilities into the already designed workflow of the inversion scheme for both Chilean and Mexican events we have worked on.
Recovering and interpreting physical parameters related to friction on subduction zones at long and short time scales is the ultimate goal of this proposal.