Ground deformation and gravimetric monitoring at Somma-Vesuvius and in theCampanian volcanic area (Italy)

This paper describes an integrated ground deformation and gravity network a imed at monitoring volcano-tectonic movements in the Campanian area (southe rn Italy). It covers an area of more than 3000 km(2), including the volcani c centres of Somina-Vesuvius, Campi Flegrei caldera and Ischia island. Leve lling, EDM and gravity networks, as well as periodic and continuous GPS mea surements are carried out. The aim of the network is twofold: monitoring gr ound deformations in the above mentioned volcanic areas, and studying the c omplex tectonics of the Campania Plain, a graben-like structure in which th e Neapolitan volcanism is concentrated, in relation to the tectonics of the Southern Apennines and of the Tyrrhenian Basin. The monitoring network con sists of larger-scale levelling, EDM and GPS networks covering the whole Ca mpania Plain, connected to the relatively stable areas of Apennines, togeth er with smaller scale networks aimed at accurately monitoring the Somma-Ves uvius volcano, one of the most dangerous over the World due to the high deg ree of urban development. The Somma-Vesuvius is monitored by levelling netw ork, over 200 km long, by periodic EDM and GPS measurements and by a smaH n etwork of continuously recording GPS receivers. Moreover, high precision gr avimetry is also employed to deep the knowledge of the dynamic framework of the area. The main results indicate that Mt. Vesuvius and the island of Is chia are currently quiescent, while Campi Flegrei are subject to significan t slow vertical ground movements, known as "bradyseism". Recently, two larg e uplifts, both of about 1.8 m, affected the area respectively in 1970-72 a nd 1982-84. (C) 2000 Elsevier Science Ltd. All rights reserved.