Imaging the Moho and Subducted Oceanic Crust at the Isthmus of Tehuantepec, Mexico, from Receiver Functions

Abstract

Using teleseismic data recorded along a transect, which we call VEOX (for Veracruz-Oaxaca seismic line), of 46 broadband stations installed across the Isthmus of Tehuantepec in southern Mexico, we obtained receiver functions and stacked them to study the Moho topography and back projected them to visualize the subducted slab geometry beneath the isthmus. We observed a back-azimuth dependent Moho thickness across the transect, particularly beneath the Los Tuxtlas Volcanic Field. Also, we observed the Cocos plate which subducts with an angle of 26° between 140 and 310 km from the trench. Comparison with regional seismicity indicates that it occurs below the oceanic crust.