Audio-magnetotelluric survey of a shallow aquifer east of Mesa del Contadero, central New Mexico
— Shari A. Kelley and Daniel J. Koning

The subsurface hydrogeology in the vicinity of Mesa Camp on the Armendaris Ranch in central New Mexico was investigated using the audio-magnetotelluric (AMT) geophysical method. Data were collected at two sites about 1 km from the camp. One-dimensional modeling of the data revealed a shallow resistive layer between the land surface and depths of 70–90 m below the land surface, a shallow conductor with a base at 100–130 m, and a deeper resistive and conductive pair below depths of 130 m. The shallow resistive layer corresponds to the vadose zone in the axial Rio Grande facies of the Sierra Ladrones aquifer. By combining the AMT data with information derived from recent geologic mapping in the area and limited drillhole logs, we present three geologically reasonable scenarios for the subsurface hydrogeology beneath Mesa Camp.