Fig. 3: 3D view of MT model.

3D view of E-W and N-S sections (a–f) through the MT-based model image of the subsurface architecture beneath the Campi Flegrei caldera. The traces of the sections are superimposed on a digital elevation model of the Campi Flegrei area. The zones defined by different resistivities are interpreted based on depth and geometry and other geological petrological and geophysical observations. A low resistive zone (C0) is beneath in the central caldera, extending below 8 km, that is bounded to the E and W by high resistivity bodies (R1). C0 is interpreted to be a zone of crystal mush with some melt, and R1 is considered to be the basement rock. The middle to upper crust is comprised of various smaller zones of contrasting resistivity. The low resistivity zones that extend up to the shallow crust (FC) are interpreted as the zones that transport the fluids and melt/magma from the deeper part of the system. Some of these melts stall, degassing and crystallizing in the upper crust (R0), and alter the sedimentary and volcaniclastic sequences within the caldera (C1 and C2). R2 represents a solidified magmatic body related to the volcanism of the CF. All visualizations of the 3D resistivity model presented in this manuscript were produced using the ParaView software package.