Lithosphere thickness and rupture mode variation along the Gulf of California, Mexico

Abstract:

We study the lithosphere thickness along the Baja California peninsula and continental northwestern Mexico in order to identify the different rupture modes along the Gulf of California. We use receiver functions (RFs) of 29 seismological stations from three networks: NARS-Baja (Network of Autonomously Recording Seismographs), RESBAN (Broadband seismic network from the Gulf of California), and SSN (National Seismological Service, Mexico). Thickness of the lithosphere varies from 43 to 89 km. The largest values are found at stations located east of Sierra Madre Occidental, and are consistent with a continental lithosphere. The thinner lithosphere is found at station NE70 (Mexicali, Mexico), consistent with a pre-rift region that has experimented serveral extension episodes. From RFs retroprojected along various profiles, we can distinguish the different rupture modes along the Gulf and identify a region under the center of the peninsula where the listhosphere has been removed by the former subduction of the Guadalupe plate.