GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 v o l c a n o e s ) i n wo r l d w i d e s i t e s ( G a l l i , 2 0 0 0 ; Ma n g a a n d Wa n g , 2 0 1 5 ) . Figure 1 – (a) Sketch of GSA transversal to the highway tunnels and passing through UL and borehole S13 area. UZ: Unsaturated Zone; SZ: Saturated Zone; KH: Karst Horizon; RA: Regional Aquiclude; T: permeability boundary (regional Thrust); UT: local thrust named Upper Thrust; WT: Water Table; HT: Highway Tunnels; UL LNGS: Underground Laboratories; BH: Borehole Hall; CA: Calderone glacier (high elevaton water reservoir – preferental recharge area); 1: overfow spring (CP: Capo Pescara spring); 2: preferental groundwater fowpath area; 3: preferental groundwater fowing toward the UL; PR: Preferental Recharge; DR: Difuse Recharge; S13, S14: monitored horizontal boreholes, S14 is located very near to S13 (HPD). The hydrogeological relatonships in the square are showed into details in (b). (b) Detailed hydrogeological relatonships between Calderone glacier actng as a water reservoir for the carbonate aquifer down below; i: hydraulic gradient; k: hydraulic conductvity (m/s) (kh: karst horizon; lim: limestone; dol: dolomite). The hydrogeological relatonships in the square are showed in detail in (c) (De Luca et al., 2018). 2. The water pressure device (HPD) and the INGV seismic staton GIGS The Borehole Hall (BH of Fig. 1), placed near UL at 965 m asl, hosts six horizontal boreholes (among which S13 and S14) and UL hosts the INGV seismic staton GIGS located at around 250 m from BH. For the purposes of this work, boreholes S13 and S14, adjacent to each other, were monitored. The borehole S13, has a horizontal length of 190 m, slopes gently upwards by ~5° and intercepts a fault near its end (UT of Fig. 1). The frst 175 m of S13 are intubated, while the last 10 m drain