“…About 60% of hydrothermal fluids recorded in the world are in the range 30 °C-70 °C, corresponding to the reservoir's depths in the range of 2-3 km, depending on local/regional geothermal gradients, and on the specific geometry and recharge mechanisms of the underground circulation paths. Below this range of depths, the weight of the overlying rocks significantly decreases porosity and permeability, hindering the onset of well-extended, and spatially Heat flow map (Lucazeau, 2019) with location of (1) thermal springs (yellow dots; after Waring, 1965;Wexsteen, et al, 1988;Ciezkowski et al, 1992;Pesce, 2005;Wang, 2008;Lahsen et al, 2010;Yousefi et al, 2010;Chandrasekharam et al, 2015), ( 2 Frontiers in Earth Science frontiersin.org continuous hydrothermal circuits (Twiss and Moores, 1997). A broad literature also confirmed that vertical permeability may significantly change under the effect of tectonic activity (e.g., among many others, Wang et al, 2016;Brogi et al, 2021): faulting induced by seismic events has been effective in generating thermal springs emissions belonging to hydrothermal systems due to rock fracturing and the availability of feeding groundwaters.…”