Exploration of the geothermal filed in the eastern Phlegrean Fields caldera for sustainability analysis of low-middle temperatures exploitation

The active volcanic area of Campi Flegrei caldera (CFc) has been the site of many geothermal investigations, since the early XX century. However, all investigations were concentrated in the western and northern sector of the geothermal system, for its characteristic of medium-high enthalpy resources. Only recently the hypothesized favorable characteristics of the eastern sector reservoir (liquid phase and almost neutral pH values) with respect to the one of the central sectors (gas dominated and acid pH values), despite the lower temperatures, allow an increasing interest in the exploration of this sector of geothermal field. So far, the Agnano caldera has been studied through the research project GeoGrid. Preliminary results from a seismic, geo-electric, gravimetric, hydro-chemical and groundwater data surveys reveal a groundwater flow from NE to SW, in full agreement with the data of scientific literature. Along the flow direction, the chemism and temperature of groundwater present discontinuous manifestations of thermal waters rich in CO2, suggesting that the local fresh groundwater receives endogenous inputs (even at high temperatures) of CO2 well correlated to important tectonic lines identified by geophysical and stratigraphic data. In future these findings could be utilised for sustainability analysis of low-middle enthalpy resource exploitation of the area.