GPS Monitoring at Vesuvio, Campi Flegrei Caldera and Ischia Island (Southern Italy)

Abstract

The Neapolitan volcanic area is located in the southern part of the Campanian plain and includes three active volcanoes (Vesuvius, Campi Flegrei Caldera and Ischia Island). This area shows different dynamical behaviours. Campi Flegrei caldera represents one well known and peculiar example of ground deformations (bradyseism), with periods of intense uplift during the 1969-72 and 1982-84, followed by subsidence phase with some episodic mini-uplifts superimposed. Contrary, Vesuvius is a substantially stable volcano, with small and localized subsidence mainly in the crater zone. Ischia Island has been characterized by subsidence in the S and NW sectors of the island. The presence of these three volcanoes in a dense populated area, makes ground deformation detection a crucial point in the risk mitigation. Ground deformation is an important volcanic precursor, because linked to magma overpressure and migration, thus, continuous monitoring and modelling is one of the main instruments to attempt for a short time forecast of eruptive activity. Since several years, the INGV – Osservatorio Vesuviano installed a permanent GPS network (NeVoCGPS), constituted of 27 stations, in the Neapolitan volcanic area with a configuration that guarantees a continuous and fast 3D information about the dynamics of the area. All the GPS stations are managed by remote control, the data are daily downloaded automatically. After an automatic quality control procedure, the data processing is performed by the Bernese Processing Engine (BPE) of the Bernese GPS software v. 5.0. In this work, the entire chain of data acquisition and processing is described and some results obtained in last years are presented.