Pressure induced temperature variations in an underground quarry

Temperature measurements have been performed in the rock and atmosphere of an underground limestone quarry in Vincennes, France. In the atmosphere, te mperature variations associated with variations of the atmospheric pressure are continuously observed, with an average coupling of 70 m degreesC/hPa a t a period of 4 min, 35 m degreesC/hPa at 1 h, and 3 m degreesC/hPa at I da y, and an increasing phase advance for increasing period. At the highest fr equencies, the coupling is close to its adiabatic value of 80 m degreesC/hP a. The reduction of coupling with decreasing frequency is interpreted as di abatic thermal stabilisation of the atmosphere by heat flow and coupled fee dback due to phase changes of water. During extreme events, such as the tem pests that occurred in France in December 1999, additional effects were obs erved in the atmosphere and in the rock material as well. Pressure induced temperature variations may be important to study in underground monitoring experiments, and may be a useful tool for the characterisation of nuclear w aste storage sites. (C) 2001 Elsevier Science B.V. All rights reserved.