The Formation

River Sentino and sulphureous waters

If the tickets available online are sold out, it is still possible to buy them at the Ticket Office of the Caves. Admission is guaranteed.
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ATTENTION! Tickets ARE NOT REFUNDABLE, in case of non-use or arrival after the time written on the ticket. It will therefore be necessary to pay another ticket for a subsequent tour.
Access to dogs is allowed only with a pet carrier, not on a leash. For large dogs, 3 concrete dog boxes with a lockable front grille with padlock are available at the ticket office parking lot.
Located in a safe and shady place, they are not guarded. The visitor can use the pit space for a limited period of time for the visit to the cave, it cannot be booked and availability is requested once they arrive on site.

The mountain group of Valmontagna and Frasassi is characterised by a folding geological motif, with a wide limestone anticlinal corresponding to the orographic relief, and narrow synclinal which correspond to valleys and plans (Pianello di Genga's area – Saint Vittore Terme's Area). Water circulation constituted by river Sentino entered these geological structures, after orogenesis events, helped by faults and “diaclasi”(wide cracks in rocks).

These rivers, obstructed by the Mountains of Frasassi, formed, at the beginning of Pleistocene, a wide lake next to Pianello di Scheggia, and getting deep through the breaks of calcareous rocks they reached the ”Evaporitici Riabliani” deposits below, made of rock-salt , chalk and bituminous levels(AGIP Burano Well). Through the millenniums the stagnant water in Pianello-Genga's area, operating deep and subjected to great Hydrostatic pushes, caused the solution of “Evaporiti Riabliani ”, melting rock-salts and chalk, splitting the latter in calcium bicarbonate and sulphureous acid (sulphureous water). Through this mechanism, the water ,enriched in depth by mineral salts , blocked by impermeable grounds, obliged by communicating vessels law, ascended along the fault plans with springs and streams in Saint .Vittore Terme, where topographic surface is lower than the feeding basin.