Recent, slow and aseismic movement of an overthrust observed in the Abel sink hole (Saint-Vallier-de-Thiey, Alpes-Maritimes, France)

Abstract The main galleries of the Abel sink hole near Grasse (Alpes Maritimes, France) are developed along a main thrust fault. The study of speleothems clearly proves a recent movement of this fault. The fractures indicate a north-south movement, they are not fossilised by new calcite. A large rock placed under the fault plane rotated during the movement. The soda straws fixed to the rock are curved. This allows an estimation of the movement speed.