Magnetotelluric measurements in the Monte Amiata region.

A preliminary magnetotelluric (MT) survey was carried out in Southern Tuscany, Italy, to delineate the resistivity structure in an area which does not belong to classic geothermal zones but is still characterized by anomalously high heat flow. The one-dimensional (1D) resistivity inversion shows a low resistivity zone characterized by high heat flow. Based on 1D resistivity information, detailed two-dimensional (2D) resistivity modelling was carried out. A reasonable 2D resistivity model was proposed for shallow depths, and was found to be in good agreement with the available geological and geophysical information on the area. The present results show a low resistivity anomaly, characterized by high heat flow. The anomaly seems to extend beyond the classic Mt. Amiata geothermal region.