1. a ARPA‐Piemonte Regional Centre for the Geological Research , Corso Unione Sovietica 216, 10134 Turin, Italy
2. b CNR‐IGG: Institute of Geosciences and Earth Resources (Sez. of Torino) , c/o Department of Earth Science , University of Torino , Via Accademia delle Scienze, 5, 10123 Turin, Italy