Gravity Interpretation of Mt.Amiata Geothermal Area (Central Italy)

Abstract

A detailed gravity survey of the Mt Amiata geothermal area is reinterpreted in order to reconstruct the deep structure of the area. The study has the aim to interpret the gravity low (-24 mgal) centered on Mt Amiata. The interpretation, based on the stripping off technique using a 3D model, shows a residual anomaly attributable to previously unidentified bodies. The presence of an anomalous body at a depth of 6 km, referable to an intrusive mass responsible for most of the negative anomaly is assumed, on the basis of the geothermal gradient in the area. Two local negative residual anomalies of -4 and -6 mgal have also been identified at Piancastagnaio and Vallerona, which are interpreted as due to density variations owing to an increase in porosity within the Tuscan carbonate formation. Those anomalieshave been associated to the geothermal field.