Seismic velocity in the Gulf of California from the analysis of Rayleigh wave group velocities

In this study we develop a broad-scale velocity model for the crust and upper mantle of the Gulf of California from seismic data recorded by the broadband NARS-Baja (14 stations) and RESBAN (5 stations) networks. Regional constraints on crust and upper mantle velocities are important for studies of the lithospheric structure and deformation. This is particularly true in target areas like the Gulf of California, where the scientific community hopes to gain a fundamental understanding of the lithospheric rupture. We measure Rayleigh waves dispersion curves of 134 earthquakes to create a 2D map of the group velocities in the region, which can then be used to determine the 3D structure. Our results show noticeable differences in the group velocities of different paths. Due to the fact that the NARS-Baja array straddles the plate boundary, we are able to make additional first-order comparisons of the crust on opposite sides of the conjugate margins.