Unrest at Campi Flegrei Caldera (Southern Italy) during the last decade

Abstract

Campi Flegrei caldera is located just west of the city of Naples, within the central-southern sector of a large graben called Campania Plain. It is an active volcanic area marked by a quasicircular caldera depression, probably formed by a huge ignimbritic eruption occurred about 39000 years ago. This caldera was generated by collapses produced by strong explosive eruptions. The only eruption in historical times occurred in 1538building a spatter cone called Mt. Nuovo. Campi Flegrei area periodically experiences significant deformation episodes, with uplift phenomena reaching more than 3.5 m in 15 years (from 1970 to 1984), which caused during 1983-84 the temporary evacuation of about 40000 people from Pozzuoli town. The structural complexity of the Campi Flegrei area, together with the evidence of a strong interaction between magmatic chamber and shallow geothermal system, calls for a detailed characterization of the substructure and of the magma-water interaction processes. The Campi Flegrei caldera is characterized by high volcanic risk due to the explosivity of the eruptions and to the intense urbanization of the surrounding area, and has been the site of significant unrest for the past 2000 years (DE NATALE et alii, 2006). The caldera floor was raised to about 1.7 meters between 1968 and 1972; then a subsidence phase of about 0.2 m occurred between 1972 and 1975 followed by a stable period until 1981. Between 1982 and 1985 new uplift occurred and the caldera rose about 1.8 m, without eruptive phenomena...