Radon measurements in soil and water in the seismic Friuli area

Radon concentration measurements have been related to seismic occurrence in a number of publications aiming to detect possible pre-seismic or co-seismic variations. Based on these studies, there is evidence that the radon emanation depends on the lithologic and rheologic parameters of the rock, which change in the preparatory stage of the seismic cycle. With the aim of having a better understanding of these relations, we have set up a station where both radon concentration in soil and deformation are being measured since September 1994. The station is located in the Villanova Cave (468158N, 138168E), 60 m below the surface. The experiment has recently been extended with a second radon station at the Arta Terme thermal baths, where measurements are made in water. A meteorological station controls the principal atmospheric parameters, which could influence radon variation. We present an analysis of the data recorded at the Villanova station, comprising the study of the local seismicity the results of which have been low throughout the recording period. Furthermore, in this study we show some preliminary results regarding the Arta Terme station