1D inversion of MT and TEM data with application of soundings from Krýsuvík, SW-Iceland and a review of MT/TEM data from Bacman geothermal project, Central Philippines : Jefferson R. Africa.

Abstract

1D joint inversion and a study of selected MT and TEM soundings from the Krýsuvík high-temperature area, SW-Iceland and the Bacon-Manito geothermal project, Central Philippines was carried out using the TEMTD program. The two areas show a significant down shifting of MT apparent resistivity curves as a result of near-surface inhomogeneity. Joint inversion sections show a good correlation of the resistivity structure with the mineral alterations seen in the intersected wells although relic alteration was observed in both cases. Inversion results highly depend on the initial model used and the parameters imposed. There exists a basement depth value where the fit of the inverted 1D model of the TEM and MT data varies significantly as depth becomes shallower or deeper than that value. The reliability of 1D joint inversion is highly dependent on the overlap of the TEM and MT data such that the downward bias of the MT apparent resistivity curve and the 3D structure effect of TEM data is reduced.