3D Inverse modeling of EM-LIN data to investigate coastal sinkholes in Quintana Roo Mexico

Abstract. In southern Mexico at the Yucatan Peninsula (YP), cities and towns are settled on a platform of calcareous sedimentary sequence which has originated a wide formation of sinkholes, underground rivers and caverns due of karst process. The anthropogenic activities threat the only source of fresh water supply which is located in a regional unconfined aquifer; there are not lakes and rivers. For sustainable use of these resources at the YP, it is required to develop mathematical tools to help the groundwater modeling. In order to determine the geometry of the aquifer as the positions of caves, sinkholes and underground rivers we have developed software to invert three-dimensional electromagnetic low-induction numbers (3D EM-LIN) data for a set of profiles at arbitrary angle. In this work we have explored with the aid of EM-LIN geophysical method, the Chac-Mool sinkhole system at the state of Quintana Roo, Mexico. We have performed inverse modeling in 3D using the EM-34 instrument for vertical and horizontal magnetic dipoles. The 3D inversion process gives us models that allow us to correlate the path of the underground rivers with the subsurface electrical resistivity. In this work we have shown that inverse modeling of EM-LIN data is necessary to explore and understand coastal karst systems.