HR: 0800h
AN: T51D-1379    [Abstracts]
TI: Velocity Model for the Gulf of California
AU: * Di Luccio, F
EM: diluccio@gps.caltech.edu
AF: Caltech, Seismo Lab, Pasadena, CA 91125 United States
AU: Clayton, R W
EM: clay@gps.caltech.edu
AF: Caltech, Seismo Lab, Pasadena, CA 91125 United States
AB: A lithosphere/upper-mantle velocity model is determined for the Gulf of California region from surface wave group velocities and receiver functions, determined from data recoded by the NARS-Baja and RESBAN seismic networks. The main features of the model are a mid-Gulf high-velocity zone, 50% thinning of the crust on the eastern side of the Baja Peninsula, and crust differences on either side of the Gulf. We have also used receiver functions to look at lateral variations in the 400 km seismic discontinuity and with less resolution the 670 km discontinuity. The surface wave group velocities are determined both from a dozen events in the greater Gulf region, and from correlations of seismic noise. For the earthquake sources, reliable measures are generally determined for periods from 10 to 100 secs. These data provide sampling from the crust to about 200 km into the mantle. For the noise source both the ocean microseism band (5 to 20 sec) and the infrasonic band (30 to 100 sec) are used. The data are correlated for several times periods and for temporal lengths varying from 15 to 99 days. The correlations provide an estimate of the Green's function of the surface wave traveling between the two stations. We generally see that the microseism band correlates in the on-shore direction and shows some complexities that may be related to multi-pathing. The longer period wave correlate in both directions and are generally somewhat simpler in structure.
DE: 7205 Continental crust (1219)
DE: 7245 Mid-ocean ridges
DE: 7255 Surface waves and free oscillations
SC: Tectonophysics [T]
MN: Fall Meeting 2005