Resistivity structure on the western side of Mt. Amiata region.

A magnetotelluric survey was carried out in southern Tuscany, Italy, on the western side of the Mt. Amiata geothermal region. The main purpose of this survey was to map the resistivity structure of an area which does not belong to the classical geothermal zones but is still characterized by anomalously high heat flow. Furthermore a recent updating of the Southern Tuscany geothermal anomalies would refer this area as a western extension of the Mt Amiata geothermal anomaly. Five components of the electric and magnetic fields have been recorded at the various locations in the area, which were few kilometers apart. The one-dimensional resistivity inversion of the data shows a low resistivity zone characterized by high heat flow. Based on one-dimensional resistivity information, detailed two dimensional resistivity modelling has been carried out. A reasonable two-dimensional resistivity model is proposed for shallow to middle depths, and it is found to be in good agreement with the available geological and geophysical informations on the area