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[MIS08-10] Possible stimulation of seismic activity by geomagnetically induced currents generated by ionizing radiation of solar flare in the illuminated hemisphere
Keywords:solar flare, geomagnetically induced current, earthquake triggering, conductive fault
In addition to traditional approach to the short-term earthquake (EQ) prediction based on a search of possible precursors of seismic event, the following steps towards EQ predictability look reasonable [Sobolev, 2011]: a) determination of an unstable area; (b) monitoring the triggering effects and assessment their impact on the unstable area; and (c) estimation of probability of location, time, and magnitude of impending EQ.
It is well-known that external factors like distant strong EQs, underground explosions, fluid injection, etc. can trigger EQ in the crust fault matured for dynamical rupture. Recently it was found that EQ triggering is possible during injection of DC pulses into the Earth crust by statistical analysis of regional seismicity during artificial electromagnetic impact [Tarasov & Tarasova] and laboratory experiments [Sobolev & Ponomarev, 2003; Novikov et al, 2017].
Numerical estimations based on a theoretical model of disturbance of electric filed, electric current, and heat release in lithosphere associated with variation of ionosphere conductivity caused by absorption of ionizing radiation of solar flares [Sorokin et al, 2019] demonstrated that solar flare can generate electric current density in lithosphere over 10–6 A/m2, that is comparable with a current density generated in the Earth crust by artificial pulsed power systems, which provide regional earthquake triggering and spatiotemporal variation of seismic activity. Therefore, EQ triggering is possible not only by man-made pulsed power sources but also by the solar flares. The results obtained were confirmed by sharp increase of global seismicity after the strong solar flare of X9.3 class on September 6, 2017 [Novikov et al, 2020].
For application of the obtained results for EQ alarm immediately after the strong solar flare in the specific seismic-prone zones we need to select the areas, most sensitive to impact of solar flare, where the maximal density of geomagnetically induced currents (GIC) will be generated in the conductive crust faults. We present the numerical model of GIC generation by ionizing radiation of solar flare in the illuminated hemisphere. Calculations of disturbance of electromagnetic field and telluric current were performed for San Andreas fault (California), integral radiant flux density of 0.005 J/m2, and the time of UTC 15:00 and 18:00 on July 20, 2020. It was found that ionosphere conductivity disturbance is 2 S and 4 S for UTC 15:00 and 18:00, respectively, that provides double increase of telluric current in the fault (1.5×10-7 and 3×10-7 A/m2). Duration of the current pulse is about 40-50 s. These parameters are comparable with the DC pulse generated in the EQ sources by artificial power system (MHD generator "Pamir-2": current density 10-7 - 10-8 A/m2 at depth of 5-10 km, DC pulse duration up to 10s) resulted in triggering of regional weak seismicity at Northern Tien Shan.
The reported study was funded by RFBR and NSFC, project number 21-55-53053.
References:
Sobolev G.A. (2011) Seismicity dynamics and earthquake predictability. Nat. Hazards Syst. Sci., 11, 445-458.
Tarasov N.T., Tarasova N.V. (2004) Spatial-temporal structure of seismicity of the North Tien Shan and its change under effect of high energy electromagnetic pulses. Annals of Geophysics, 47, 1, 199-212.
Sobolev G.A., Ponomarev A.V. (2003) Physics of earthquakes and precursors. Moscow, Nauka, 269 p (in Russian).
Novikov V.A., Okunev V.I., Klyuchkin V.N., Liu J., Ruzhin Yu.Ya., Shen X. (2017) Electrical triggering of earthquakes: results of laboratory experiments at spring-block models. Earthq. Sci. 30, 4, 167-172.
Sorokin V.M., Yashchenko A.K., Novikov V.A. (2019) A possible mechanism of stimulation of seismic activity by ionizing radiation of solar flares. Earthq. Sci., 32, 1, 26-34.
Novikov V., Ruzhin Yu., Sorokin V., Yaschenko A. (2020) Space weather and earthquakes: possible triggering of seismic activity by strong solar flares. Annals of Geophysics, 63, 5, PA554.
It is well-known that external factors like distant strong EQs, underground explosions, fluid injection, etc. can trigger EQ in the crust fault matured for dynamical rupture. Recently it was found that EQ triggering is possible during injection of DC pulses into the Earth crust by statistical analysis of regional seismicity during artificial electromagnetic impact [Tarasov & Tarasova] and laboratory experiments [Sobolev & Ponomarev, 2003; Novikov et al, 2017].
Numerical estimations based on a theoretical model of disturbance of electric filed, electric current, and heat release in lithosphere associated with variation of ionosphere conductivity caused by absorption of ionizing radiation of solar flares [Sorokin et al, 2019] demonstrated that solar flare can generate electric current density in lithosphere over 10–6 A/m2, that is comparable with a current density generated in the Earth crust by artificial pulsed power systems, which provide regional earthquake triggering and spatiotemporal variation of seismic activity. Therefore, EQ triggering is possible not only by man-made pulsed power sources but also by the solar flares. The results obtained were confirmed by sharp increase of global seismicity after the strong solar flare of X9.3 class on September 6, 2017 [Novikov et al, 2020].
For application of the obtained results for EQ alarm immediately after the strong solar flare in the specific seismic-prone zones we need to select the areas, most sensitive to impact of solar flare, where the maximal density of geomagnetically induced currents (GIC) will be generated in the conductive crust faults. We present the numerical model of GIC generation by ionizing radiation of solar flare in the illuminated hemisphere. Calculations of disturbance of electromagnetic field and telluric current were performed for San Andreas fault (California), integral radiant flux density of 0.005 J/m2, and the time of UTC 15:00 and 18:00 on July 20, 2020. It was found that ionosphere conductivity disturbance is 2 S and 4 S for UTC 15:00 and 18:00, respectively, that provides double increase of telluric current in the fault (1.5×10-7 and 3×10-7 A/m2). Duration of the current pulse is about 40-50 s. These parameters are comparable with the DC pulse generated in the EQ sources by artificial power system (MHD generator "Pamir-2": current density 10-7 - 10-8 A/m2 at depth of 5-10 km, DC pulse duration up to 10s) resulted in triggering of regional weak seismicity at Northern Tien Shan.
The reported study was funded by RFBR and NSFC, project number 21-55-53053.
References:
Sobolev G.A. (2011) Seismicity dynamics and earthquake predictability. Nat. Hazards Syst. Sci., 11, 445-458.
Tarasov N.T., Tarasova N.V. (2004) Spatial-temporal structure of seismicity of the North Tien Shan and its change under effect of high energy electromagnetic pulses. Annals of Geophysics, 47, 1, 199-212.
Sobolev G.A., Ponomarev A.V. (2003) Physics of earthquakes and precursors. Moscow, Nauka, 269 p (in Russian).
Novikov V.A., Okunev V.I., Klyuchkin V.N., Liu J., Ruzhin Yu.Ya., Shen X. (2017) Electrical triggering of earthquakes: results of laboratory experiments at spring-block models. Earthq. Sci. 30, 4, 167-172.
Sorokin V.M., Yashchenko A.K., Novikov V.A. (2019) A possible mechanism of stimulation of seismic activity by ionizing radiation of solar flares. Earthq. Sci., 32, 1, 26-34.
Novikov V., Ruzhin Yu., Sorokin V., Yaschenko A. (2020) Space weather and earthquakes: possible triggering of seismic activity by strong solar flares. Annals of Geophysics, 63, 5, PA554.