Three-Dimensional Inversion of ZTEM Data at the Elevenmile Canyon Geothermal System, Nevada

Abstract

The Elevenmile Canyon area in Nevada is a potential geothermal resource. Electrical conductivity may be a diagnostic property that is indicative of geologic structure, alteration, or fluids, and this has motivated the collection of ZTEM data over the area. Those data have been inverted with a 3D algorithm. The main structural feature is a large conductor that runs through the survey area. Analyses performed here provide confidence that the conductor exists but some details, such as its depth and absolute conductivity, are less well determined. These features are affected by the choice of reference model used for the ZTEM inversion. To help define an appropriate reference model, we use a calibration point from a DC resistivity sounding. The final output is our best estimate for the 3D conductivity structure in the area. The highly conductive areas are possibly connected with geothermal fluids along faults. However, the interpretation of the conductive zone, and other features in our 3D model, will require further geophysical and geological work in the Elevenmile Canyon area.