Abstract
The main galeries of the Abel sinkhole near Grasse (Alpes Maritimes - France) are developped along a main thrust fault. The study of speleothems proves clearly 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 sodastraws fixed to the rock are curved. This allows an estimation of the movement speed.