HR: 1340h
AN: S53A-0181    [Abstracts]
TI: Nonlinear Source Tomography Of The Mw=8.4, 23 June 2001 Arequipa, Peru, Earthquake.
AU: * Sladen, A
EM: sladen@geologie.ens.fr
AF: Laboratoire de G\'{e}ologie de l'ENS, 24 rue Lhomond, Paris, 75231 France
AU: Madariaga, R
EM: madariag@geologie.ens.fr
AF: Laboratoire de G\'{e}ologie de l'ENS, 24 rue Lhomond, Paris, 75231 France
AU: Cl\'{e}v\'{e}d\'{e}, E
EM: clevede@ipgp.jussieu.fr
AF: Institut de Physique du Globe, 4, place Jussieu, Paris, 75252 France
AB: We investigate on the rupture process of the $Mw=8.4$ tsunami-genic earthquake of June 23, 2001 in Arequipa, Peru, putting special emphasis on the determination of rupture velocity. Since the determination of rupture velocity is nonlinear we use the Neighbourhood algorithm for the inversion. We use 16 broad band far field seismograms band pass filtered between 0.01 and 0.4$Hz$. The goodness of the fit between observed and synthetics is mesured with an $L^2$ norm. The fault is parameterized with a model containing 57 patch of size $9\times 20km$. Because of computer time problems the final steps in the inversion, once the solution has converged to a well defined minimum, are done with a downhill simplex algorithm. The best solution for this unilateral event is found to have propagated southward at a very low speed ($1,6km/s$) with $80%$ of the final moment released as one patch $80s$ after the onset of rupture. The general features of the inversion are compatible with results of linearized inversion and the slow rupture speed is similar to that observed for tsunami earthquakes. The location of the main energy patch is confirmed by a CMT grid search over the whole area of rupture and by tsunami observations.
DE: 7230 Seismicity and seismotectonics
DE: 7260 Theory and modeling
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting