Integrated geophysical techniques to image short-to very short-term ground deformation associated with unrest at coastal calderas: a case study from the Pozzuoli Bay, Campi Flegrei, South Italy

摘要

Campi Flegrei is an active, large (about 200 km~2) volcanic complex located offshore in the northern sector of the Naples Bay. The inner, peri-calderic area is characterized by severe, non-linear ground deformation and associated displacement of manufacts (bradyseism). Here we show the results of marine geophysical surveys (multibeam swath bathymetry) and satellite observations (SAR Interferometry) aimed at the detection and measurement of the coastal horizontal and vertical displacements of segments compounding the Pozzuoli Bay, and mostly corresponding to the inner part of the Campi Flegrei Caldera. Radar satellite observations provided a means for the definition of both regional and local displacement (uplift and/or subsidence) of discrete areas and associated infrastrucures (e.g. buildings, landmarks, archeological remains) on the emerged portion of the caldera structure, thus allowing for the understanding of the active trends of bradyseism for each coastal segment over the last 25 years. At same time, high-resolution multibeam swath bathymetry provided unprecedented accurate imaging of geomorphological lineaments, as well as of the Roman archaeological outliers presently extending over the seafloor. These data served as a constrain to reconstruct the evolution of vertical displacements in the coastal sector of the Pozzuoli Bay over the last 2.000 years ca. The integration of datasets also offers sound base information to define the recentmost-to-current trends of ground deformation at Campi Flegrei.