1. Measurements made at or near the earth’s surface of natural or induced electric fields, the objective usually being to map mineral concentrations or for geologic or basement mapping. See Figure E-7 and electric profiling, electric sounding, electromagnetic method, induced-polarization method, magnetotelluric method, resistivity method, self-potential method, telluric current method. 2. Electric log (q.v.) run in a borehole.