Earth Planets Space, Vol. 53 (No. 5), pp. 385-396, 2001

Geomagnetic depth sounding in the Northern Apennines (Italy)

E. Armadillo¹, E. Bozzo¹, V. Cerv³, A. De Santis², D. Di Mauro², M. Gambetta¹, A. Meloni², J. Pek³, and F. Speranza²

¹Dipartimento per lo studio del terrirorio e delle sue risorse, Viale Benedetto XV, 5-16132 Genova, Italy
²Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605-00143 Rome, Italy
³GFU CSAV, 141 31 Praha 4, Czech Republic

(Received January 11, 2000; Revised January 11, 2001; Accepted February 6, 2001)

Abstract: A Geomagnetic Depth Sounding (GDS) survey covering the Northern Apennines of Italy has been carried out in the period 1992-94. Induction arrows maps and hypothetical event Fourier maps were constructed to obtain an electromagnetic imaging of this area. Since the two dimensional (2-D) character comes out from those maps for periods greater than 32 minutes, a 2-D inverse modeling was carried out. The model responses show that a deep conductive layer (>5000 S) underlies the Apennine chain at about 20 km depth. The transition between the Adriatic and the Tyrrhenian domains is marked by a rather sharp vertical offset in this conducting layer. In the northwest sector of the studied area an anomalous high conductivity behavior is superimposed on the regional trend, which corresponds to the geothermal field of Larderello-Travale.