Evidence of precursor phenomena in the Kobe earthquake obtained from atmospheric radon concentration

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.

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Radon degassing triggered by tidal loading before an earthquake

Scientific Reports ◽

10.1038/s41598-021-83499-0 ◽

2021 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Yasutaka Omori ◽

Hiroyuki Nagahama ◽

Yumi Yasuoka ◽

Jun Muto

Keyword(s):

Earthquake Prediction ◽

Radon Concentration ◽

Quantitative Relationship ◽

Stress Regime ◽

Crustal Stress ◽

Crustal Fluid ◽

Kobe Earthquake ◽

Long Time ◽

Tidal Loading ◽

Atmospheric Radon

AbstractThe presence of anomalous geochemical changes related to earthquakes has been controversial despite widespread, long time challenges for earthquake prediction. Establishing a quantitative relationship among geochemical changes and geodetical and seismological changes can clarify their hidden connection. Here we determined the response of atmospheric radon (222Rn) to diurnal tidal (K1 constituent) loading in the reported 11-year-long variation in the atmospheric radon concentration, including its anomalous evolution for 2 months before the devastating 1995 Kobe earthquake in Japan. The response to the tidal loading had been identified for 5 years before the occurrence of the earthquake. Comparison between these radon responses relative to crustal strain revealed that the response efficiency for the diurnal K1 tide was larger than that for the earthquake by a factor of 21–33, implying the involvement of crustal fluid movement. The radon responses occurred when compressional crustal stress decreased or changed to extension. These findings suggest that changes in radon exhaled from the ground were induced by ascent flow of soil gas acting as a radon carrier and degassed from mantle-derived crustal fluid upwelling due to modulation of the crustal stress regime.

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Anomalous change in atmospheric radon concentration sourced from broad crustal deformation: A case study of the 1995 Kobe earthquake

Applied Geochemistry ◽

10.1016/j.apgeochem.2011.12.018 ◽

2012 ◽

Vol 27 (4) ◽

pp. 825-830 ◽

Cited By ~ 4

Author(s):

Yumi Yasuoka ◽

Yusuke Kawada ◽

Yasutaka Omori ◽

Hiroyuki Nagahama ◽

Tetsuo Ishikawa ◽

...

Keyword(s):

Crustal Deformation ◽

Radon Concentration ◽

Anomalous Change ◽

Kobe Earthquake ◽

Atmospheric Radon

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A long-term investigation of the atmospheric radon concentration in Beijing, China

Journal of Radiological Protection ◽

10.1088/0952-4746/29/2/012 ◽

2009 ◽

Vol 29 (2) ◽

pp. 263-268 ◽

Cited By ~ 3

Author(s):

Liang Zhang ◽

Liguo Zhang ◽

Qiuju Guo

Keyword(s):

Radon Concentration ◽

Beijing China ◽

Atmospheric Radon

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Non-parametric detection of atmospheric radon concentration anomalies related to earthquakes

Scientific Reports ◽

10.1038/s41598-018-31341-5 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 4

Author(s):

Daichi Iwata ◽

Hiroyuki Nagahama ◽

Jun Muto ◽

Yumi Yasuoka

Keyword(s):

Radon Concentration ◽

Atmospheric Radon ◽

Non Parametric

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Anomalous radon emanation linked to preseismic electromagnetic phenomena

Natural Hazards and Earth System Science ◽

10.5194/nhess-7-629-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 629-635 ◽

Cited By ~ 44

Author(s):

Y. Omori ◽

Y. Yasuoka ◽

H. Nagahama ◽

Y. Kawada ◽

T. Ishikawa ◽

...

Keyword(s):

Electric Field ◽

Power Law ◽

Radon Concentration ◽

Damage Evolution ◽

Atmospheric Electric Field ◽

Ionospheric Disturbances ◽

Radon Emanation ◽

Radon Anomaly ◽

Large Earthquakes ◽

Atmospheric Radon

Abstract. Anomalous emanation of radon (222Rn) was observed preceding large earthquakes and is considered to be linked to preseismic electromagnetic phenomena (e.g. great changes of atmospheric electric field and ionospheric disturbances). Here we analyze atmospheric radon concentration and estimate changes of electrical conditions in atmosphere due to preseismic radon anomaly. The increase of radon emanation obeys crustal damage evolution, following a power-law of time-to-earthquake. Moreover, the radon emanation decreases the atmospheric electric field by 40%, besides influencing the maximum strength of atmospheric electric field by 104–105 V/m enough to trigger ionospheric disturbances. These changes are within the ranges observed or explaining electromagnetic phenomena associated with large earthquakes.

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