1-D joint inversion of MT and TEM data with examples from the Krýsuvík area, Reykjanes penisula, SW-Iceland

Abstract

Electrical resistivity methods are widely applied in geothermal exploration. Any progressive work like exploration drilling in an area under study is always based on surface exploration results. In geophysical prospecting of geothermal systems, several geophysical exploration methods are applicable. This report focuses on the use of resistivity methods based on application of electromagnetic currents, such as Transient Electromagnetic (TEM) and Magnetotelluric (MT) methods, but other methods are also introduced and discussed briefly. For tens of years, electromagnetic resistivity methods have turned out to be the most effective investigation tool in resolving anomalous subsurface resistivity structures associated with geothermal activity. In this report, a discussion of the fundamental principles and field practices involved in the different resistivity methods of interest are presented. Existing TEM and MT resistivity data from Krýsuvík high-temperature geothermal area, SW-Iceland were interpreted and presented. Soundings were selected along a NW-SE profile through the area. The TEM data were inverted for 1-D, and a 1-D joint inversion of the MT and TEM data was also performed. A general interpretation of the results gives a plausible description of the resistivity structure of the study area.