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, temperature variations associated with variations of the atmospheric pressure are continuously observed, with an average coupling of 70 m°C/hPa at a period of 4 min, 35 m°C/hPa at 1 h, and 3 m° C/hPa at 1 day, and an increasing phase advance for increasing period. At the highest frequencies, the coupling is close to its adiabatic value of 80 m°C/hPa. The reduction of coupling with decreasing frequency is interpreted as diabatic thermal stabilisation of the atmosphere by heat flow and coupled feedback due to phase changes of water. During extreme events, such as the tempests that occurred in France in December 1999, additional effects were observed 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 waste storage sites.