Abstract: A three-dimensional display and interpretation technique, in which magnetotelluric survey and modeling data are transformed and compared in order to yield a remotely determined picture of subsurface rock properties and structure, is disclosed. Normalized transfer functions for the magnetotelluric fields are displayed, as normalized impedance polar diagrams, properly oriented at appropriate probing depths using a logarithmic vertical coordinate. The form of these and other normalized polar diagrams provide geologic information on local-structure dimensionality. Colors are derived and assigned to particular azimuthal segments of the normalized impedance polar diagrams in order to identify rock properties in particular directions at depth. This unique combination results in structural and rock property information being simultaneously displayed in a single trace.

Abstract: A method of geothermal exploration in which the arrival times of reflected seismic waves and voltage differences caused by subsurface current flow are detected and processed to provide useful estimates of subsurface porosity, pore-fluid resistivity and equivalent salinity as functions of position.