Ground deformation due to tectonic, hydrothermal, gravity, hydrogeological, and anthropic processes in the Campania Region (Southern Italy) from Permanent Scatterers Synthetic Aperture Radar Interferometry

Abstract

We apply the Permanent Scatterers Synthetic Aperture Radar Interferometry (PSInSAR) technique to the Campania Region (Southern Italy), which includes the Southern Apennines chain and Plio-Quaternary structural depressions, with the aim to detect ground displacements at a regional scale. The study area, which extends for 13600 km2, is characterized by intense urbanization, active volcanoes (Phlegraean Fields, Vesuvius and Ischia), seismogenic structures, landslides, hydrogeological instability. PSInSAR technique allows us to identify a set of radar benchmarks (PS) where accurate displacement measurements can be carried out. About 1.7 106 PS are identified by processing Synthetic Aperture Radar (SAR) images acquired in ascending and descending orbits from 1992 to 2001 by the European Remote Sensing satellites (ERS). The PSInSAR application at regional scale detected ground deformations ranging from +28 to −39 mm/yr. The calculated velocity values are consistent with the available GPS and levelling data from selected areas. We identify volcanic areas in which the deformation is mainly related to the depressurization of the local hydrothermal systems, and recognize deformations along seismogenic and aseismic NNW-SSE and NW-SE faults. The deformations localized along the Southern Apennines chain are mainly related to landslides while those occurring in the plains are due to subsidence processes induced by intensive drainage from wells, i.e. anthropic activity. The review of 9 years of SAR data show that tectonic, volcanic/hydrothermal, gravity, and anthropic processes are responsible for the ground deformation of Campania. The proposed joint interpretation of deformation fields related to natural and anthopogenic factors provides a comprehensive view of the dynamics of the Earth surface.