The last forty years of surface deformation at Campi Flegrei caldera: two simple stationary sources are enough

Abstract

The Campi Flegrei (CF) caldera is one of the world’s most active caldera; in this area the volcanic risk is extremely high, because of its location in a densely populated area about 15 km west of Naples inside the Campanian Plain. This caldera is renowned for its long historical activity that includes earthquakes, eruption and intense unrest episodes. The source of the observed surface deformation at Campi Flegrei has been and is a matter of debate, particularly in the last two years (2011-2013) because of a considerable uplift ( 15cm) that have drawn attention from both the scientists and civil protection. In such a context, my thesis has been focused to find a simple model source that explains the CF deformation field during the last forty years (1970-2013), analyzing different types of data. The positive bradyseism crisis of 1982-1984 and the negative bradyseism of 1995-2000, in particular, are investigated. Different periods are covered by different types of data, from 1970 to 1994 by leveling data, in 1980 and in 1983 by geodetic precise traversing data, from 1993 to 2010 by Synthetic-Aperture Radar (SAR) data and finally from 2000 to October 2013 by continuous Global Positioning System (cGPS). The first part of the thesis consists of a description of the deformation history of CF and the state of the art. Different models for earthquake volcano deformation, used to explain the CF phenomenology and two kinds of Monte Carlo inversion methods to determine the model source, are introduced. In the second part, the results of the analysis and of the inversion are described. Firstly the period 1970-2010 is analyzed, using leveling, geodetic precise traversing and SAR data, and subsequently cGPS data for the 2000-2013 period are used to confirm the found model... [edited by author]