The experimental investigation of soil gas radon migration mechanisms and its implication in earthquake forecast

Abstract

Laboratory experiments were performed to help understand the fluctuations and the spike-like anomalies of Rn in a time series that was recorded continuously at monitoring stations. One of the experiments indicated that Rn is adsorbed on the surface of sand particles and can be liberated with minor changes in the physical conditions of the containing medium. Another experiment indicated that the liberation of ultra-trace Rn, adsorbed on the surface of sand, was not very sensitive to small temperature and pressure changes but was responsive to the flow of carrier gases. Among the carrier gases tested, CO 2 was preferred because it has a boiling point similar to that of Rn. However, all other gases that are inert to Rn can also be carrier gases. Temperature variation in the supra soil layer can be measured fairly accurately inside double-insulated PVC pipes that also house the Rn detecting system. Temperature variation appears to be related to localized strain heating that is a part of the earthquake energy variation cycle. Up-flow of soil gas, caused by the strain heating, induced the sudden release of Rn, which thus appears as a spike-like anomaly. The migration of soil gases is expected to follow the thermal cycle corresponding to each earthquake cycle. Therefore, the spike-like anomalies can be used, in conjunction with the temperature variation cycle, as time markers to forecast the time, place, and magnitude of a coming earthquake.

The origin and detection of spike-like anomalies in soil gas radon time series

“…If stress is propagated outward from hypocenter, in a circular fashion, and the velocity of migration decreases logarithmically, then the timing of the arrival of the stress at a given site as indicated by this radon spike-like anomaly can be used to calculate the distance to the origin of the stress. By solving simultaneous equations with distances to hypocenter, time stress moving away from the hypocenter, and radon release time as unknowns, the magnitude and time of the earthquake could be estimated (Chyi et al, 2007(Chyi et al, , 2010.…”

Fractal Analysis of Pre-Seismic Electromagnetic and Radon Precursors: A Systematic Approach

“…Most importantly, according to [16,27,43,44] , the radon anomalies of the earthquake 33 of Table 2, were not detected only with active techniques but also through passive ones. It is significant to note also, that in the radon related earthquake literature, the methods that are used for processing the radon signals are, mostly, statistical or visual [46,[75][76][77][78][79].…”

Seasonal emanation of radon at Ghuttu, northwest Himalaya: Differentiation of atmospheric temperature and pressure influences

“…Increased diffusion of radon from rocks in response to the stress-induced deformation or due to the opening of microcracks and influx of fluids (Scholz et al, 1973) are considered possible mechanisms for the generation of a precursory signal in radon accompanying seismic activity (Thomas 1988;Ghosh et al, 2009;Chyi et al, 2010). Recognising these potential roles in earthquake precursory programs, a radon monitoring was initiated at Ghuttu, northwest Himalaya in 2007.…”