Maps of the study area. (a) Geo-lithological map of the Mt. SV area superposed on the SRTM DEM model. Azure areas: outcropping carbonate aquifers; orange areas: lavas; both the outlines are taken from Bucci et al. (2021). Red lines: faults according to the ITHACA database (http://portalesgi.isprambiente.it/lista-servizi-wms/Natural%20Hazard). Blue arrows: main underground drainage network in the carbonate aquifers according to Celico et al. (1998). Inset shows the position of map 1a with respect to the Italian peninsula. (b) Relative gravity (blue dots) and NeVoCGNSS (yellow crosses; after De Martino et al. 2021) networks of Mt. SV volcano. For sake of simplicity the labels of the Vesuvius area report just the number of the station but not its prefix GVES (in the following figures the station number is reported together with the prefix GVES). Dark blue and light blue squares are the position of S. Sebastiano and Lufrano water wells, respectively. Red circle is the position of the deep drilling of Trecase. The red-dotted line represents the Mt. Somma caldera rim. Rain gauge stations are reported by the black triangles. Coordinate system of maps is UTM 33 N.