HR: 1330h
AN: S42E-0219    [PDF]
TI: A teleseismic analysis of the Tecoman, Colima earthquake (22/06/2003, Mw7.4), by using surface and body waves inversion
AU: * GOMEZ-GONZALEZ, J M
EM: gomez@geociencias.unam.mx
AF: Centro de Geociencias, Campus Juriquilla-UNAM, Blvd. Villas del Mes˘n s/n, Queretaro, Qro 76230 Mexico
AU: Guzman-Speziale, M
EM: marco@geociencias.unam.mx
AF: Centro de Geociencias, Campus Juriquilla-UNAM, Blvd. Villas del Mes˘n s/n, Queretaro, Qro 76230 Mexico
AU: Sladen, A
EM: sladen@geologie.ens.fr
AF: Laboratoire de G‚ologie, Normale Sup‚rieure de Paris, 24, rue Lhomond, Paris, 75252 France
AU: Bukchin, B
EM: boris@mitp.ru
AF: International Institute for Earthquake Prediction Theory and Mathematical Geophysics, Warshavskoyesh.79 kor. 2, Moscow, 113556 Russian Federation
AU: Mostinski, A
EM: mostinsk@mitp.ru
AF: International Institute for Earthquake Prediction Theory and Mathematical Geophysics, Warshavskoyesh.79 kor. 2, Moscow, 113556 Russian Federation
AB: We studied the rupture process of the Tecoman, Colima, Mexico, earthquake (01/22/2003, Mw = 7,4), using surface and body wave inversion at teleseismics distances. In the case of body waves we used a classical approach of amplitude and waveform inversion. The point source solution gives a thrust fault plane of strike=274, dip=27, rake=75, h=26 km, and a scalar moment of Mo=1.3E+20 N m. This event shows a small directivity effect, possible because rupture occurred mainly along dip. Thus, is contrary to most mexican subduction earthquakes which propagate along the trench. The propagation path could be the reason this earthquake affected a large area of the Mexican territory. The source time function for point source solutions shows a duration of 20 s. In order to complete the solution we also inverted surface waves by obtaining the seismic moments of order 2, for intermediate periods between 50 and 100 s. This method has been successfully applied to intraplate earthquakes under the assumption of weak crustal variations. In the case of interplate earthquakes the crustal complexity is increased by the subducting plate, so we test the resolution of the method under more complex conditions. The surface waves solution is close to what we obtained by body waves having a strike=313, dip=33, rake=114, h=28 km and a Mo=1.0E+20 N m. In addition, the higher order moments define an integral duration of the 10 s, an instantaneous centroid velocity 3.2 km/s, a major axis length of 50 km, and a smaller axis of 18 km. The signal fitting in both cases is reasonably good. We also describe the seismic behavior of the earthquake, and calibrate the surface wave method in order to know its contribution to the study of subduction earthquakes.
DE: 7200 SEISMOLOGY
DE: 7205 Continental crust (1242)
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting