Time-scale invariant changes in atmospheric radon concentration and crustal strain prior to a large earthquake

Abstract

Abstract.Prior to large earthquakes (e.g. 1995 Kobe earthquake, Japan), an increase in the atmospheric radon concentration is observed, and this increase in the rate follows a power-law of the time-to-earthquake (time-to-failure). This phenomenon corresponds to the increase in the radon migration in crust and the exhalation into atmosphere. An irreversible thermodynamic model including time-scale invariance clarifies that the increases in the pressure of the advecting radon and permeability (hydraulic conductivity) in the crustal rocks are caused by the temporal changes in the power-law of the crustal strain (or cumulative Benioff strain), which is associated with damage evolution such as microcracking or changing porosity. As the result, the radon flux and the atmospheric radon concentration can show a temporal power-law increase. The concentration of atmospheric radon can be used as a proxy for the seismic precursory processes associated with crustal dynamics.

Anomalous radon emanation linked to preseismic electromagnetic phenomena

“…Moreover, the similar tendency is shown from the analysis of the daily minimums ( Fig. 2 in Kawada et al, 2007). Therefore we consider the anomaly during the three periods to be seismic related.…”

“…The change relates to the damage process in the crust (e.g. Ben-Zion and Lyakhovsky, 2002;Turcotte et al, 2003), and being a critical phenomenon prior to large earthquakes, shows a time-scale invariance, i.e., the temporal power-law (Kawada and Nagahama, 2006;Kawada et al, 2007). Furthermore, the inflection point in Fig.…”

“…where C R , t, and t c are the smoothed residual value of atmospheric radon concentration, time, and the occurrence time of the Kobe earthquake, respectively (see also Kawada et al, 2007). The other variables, C 1 , C 2 , C 3 , and δ are constants.…”

Spatiotemporal multifractal characteristics of electromagnetic radiation in response to deep coal rock bursts

“…(2004b) found that the critical characteristics of EM were determined by the nonlinear multi-fracture of discrete materials. From the thermodynamic view of irreversible damage evolution, Kawada et al (2007) introduced dipoles and explained the critical phenomena of EM emission and their timescale invariance theoretically. This research is of significance for the explanation of EMR critical characteristics before seismic events or during rock fracture.…”

“…The critical phenomena and fractal characteristics of EMR have been observed before seismic or rock fracture Rabinovitch et al, 2001;Kapiris et al, 2003;Uritsky et al, 2004;Kapiris et al, 2004a, b;Gotoh et al, 2004;Eftaxias et al, 2007;Muto et al, 2007). Some scholars have considered that the critical phenomena of EM emission are related to crack opening and expansion, as well as fractal structure Nanjo and Nagahama, 2004a, b;Kapiris et al, 2004a, b;Morgounov and Malzev, 2007;Kawada et al, 2007;Minadakis et al, 2012). Uritsky et al (2004) proposed a simple framework for modeling ultra-low frequency (ULF) electromagnetic emission signals associated with abrupt changes in the large-scale geometry of stress distribution before characteristic seismic events.…”