Systematics of radon at the Wairakei geothermal region, New Zealand

Environmental monitoring of radon in soil during a very seismically active period occurred in South West Greece

This paper focuses on the environmental monitoring of radon in soil as a potential trace gas in the search of earthquake precursors. The paper reports the following: (a) Pre-monitoring experiments. (b) Set-up of methods and devices. (c) Active and passive monitoring results concentrating on two extremely-strong radon anomalies (~ 500 kBq m(-3)). (e) Discussion regarding the employed ± 2σ technique for identifying radon disturbances. (f) Application of wavelet-power-spectrum fractal analysis for detecting power-law behaviour. The strong anomalies exhibited anti-persistent power-law-beta-values (b = (1.8 ± 0.2), b = (1.8 ± 0.3)) significantly higher than those of the baseline. Persistent b-values were also detected. The findings comply with a self-organised-critical pre-earthquake state. (h) Discussion on models that interpret the radon anomalies focusing on the recently-proposed asperity-model. (i) Application of a recent technique which showed that the two strong disturbances were proportional to the strain change. It was concluded that the strong radon disturbances may be linked to the strong earthquake of 8/6/2008, M = 6.5, occurred 29 km away from the installed instrumentation.

Indoor radon concentration in geothermal areas of central Italy

The indoor radon ((222)Rn) activity concentration was measured between January and June in the schools of two geothermal areas in Tuscany, central Italy. One of these areas (the Larderello area) is characterized by a large number of geothermal power plants, covering about 9% of the world's geothermal power production. In contrast, the other area, Monte Pisano, has not any such facilities. About 250 measurements were made using track etch detectors. Only a slight difference in the concentrations between the two major sampling areas (98 Bq m(-3) for Larderello area and 43 Bq m(-3) for Monte Pisano area) was found, and this was related to different geological characteristics of the ground and not the presence of the geothermal plants. The measured radon concentrations were always well below the intervention levels in both areas, and health risks for students and personnel in the examined schools were excluded.