Fig. 1
a Vulcano Island map; the white lines in the inset represent the main faults; the profile AA’ (black line) defines the vertical section of the axis-symmetric domain. b Simplified scheme of the complex geological structure of Vulcano Island along the AA’ section. Six regions with different hydrological properties were defined: FC (porosity: 0.1; permeability: 5 × 10–14 m2), AP (porosity: 0.15; permeability: 10–14 m2), CP (porosity: 0.15; permeability: 5 × 10–14 m2), TL (porosity: 0.15; permeability: 5 × 10–15 m2), PY (porosity: 0.45; permeability: 10–14 m2), and PL (porosity: 0.15; permeability: 5 × 10–15 m2)