Active deformation in Naples Bay evidenced by joined high-resolution marine geophysics and InSAR processing

摘要

An integrated marine geophysics and satellite remote sensing study of Naples Bay (Italy) has been carried out to evaluate the presence, magnitude, areal extent and activity of the Naples Active Deformation Line (NADEL), a structural bend affecting the post Last Glacial Maximum (L GM) sedimentary sequences. Sparker high-resolution mono-channel profiles and multibeam swath bathymetric data were acquired during the SAFE_2014 research cruise, carried out on board of the Urania R/V of CNR on August 2014. The marine geophysical study was integrated with the ground deformation field of the emerged sectors of the study area (Sorrento Peninsula and Campi Flegrei), derived by Synthetic Aperture Radar interferometry (InSAR) data, referred to the 1993-2000 and 2003-2010 time periods. The InSAR data obtained from the ERS, RADARSAT and ENVISAT images were processed with the method of Permanent Scatterers (PS). Marine geophysical data provide evidence of morphological and stratigraphicfeatures extending for about 18 km along a N130E strike. The NADEL deformation bend divides a NE offshore area, characterized by a flat morphology (slope< 1°, on average) from a SW sector, where the slope at >180 m below the sea level is, on average, 1.5°). In the area located SW of NADEL, the slopes are morphologically characterized by the presence of the uppermost active branches of the Magnaghi canyon, which are bounded upward by the presence of the NADEL pattern. Thus, we suppose that the emplacement of the Magnaghi branches and NADEL are linked. InSAR data show that a similar deformation pattern can be detected also inland, in the distal sectors located NW and SE from the NADEL edges. The NADEL segments also affect the distal SW sector of the Campi Flegrei active caldera and the carbonate units cropping out in the Sorrento Peninsula, thus extending in length for more than 40 km.