Occam and Bostick 1-D inversion of magnetotelluric soundings in he Chicxulub Impact Crater, Yucatán, Mexico

Abstract

The subsurface structure of the southeastern sector of the Chicxulub impact crater is investigated by ten magnetotelluric (MT) soundings distributed along a radial 92.5 km profile oriented SE-NW from the approximate center of the crater at Chicxulub Puerto. In general, MT soundings are one-dimensional, with Tipper magnitudes well below 0.2. Three contiguous soundings present a slight anisotropy and the largest Tipper values at frequencies lower than 0.06 Hz. This defines the structural rim of the crater at the cenote ring zone. Resistivities are respectively higher and lower than 150 ohm-m outside and inside the cenote ring. One-dimensional modeling using Bostick and Occam inversion yields similar geoelectrical models and is justified for most sites as a first approximation.