Prof.  Victor  Novikov
Joint Institute for High Temperatures of Russian Academy of Sciences (RAS), Moscow,  Russia

Title: Electromagnetic Triggering of Earthquakes by Severe Space Weather: New Results and Implications for Short-Term Earthquake Forecasting

Abstract:

Theoretically it was shown that a solar flare can cause the pulsations of geomagnetic field (GMF) and a burst of telluric currents in seismogenic faults [1,2] comparable in density to electric currents in the Earth's crust generated by an artificial source and resulted in a spatiotemporal redistribution of regional seismicity [3]. As a verification of the proposed approach the statistical analysis of impact of the top 50 solar flares (SF) of X-class (1997-2023) on the global seismic activity, as well as on the earthquake (EQ) preparation zones located in illuminated part of the globe and in the area of 5000 km radius around the subsolar point (SSP) was carried out. It is shown by a method of epoch superposition that for all cases the increase of seismicity is observed, especially in the region around the SSP (up to 38%) during 10 days after the SF in comparison with preceding 10 days [4]. Based on the field and laboratory results it is clear that the dynamic and electromagnetic (EM) triggering of EQs is possible when the earth’s crust is in the subcritical stress-strain state. Usually, it occurs in the local aftershock areas of strong EQs during the stress redistribution after the main shock. The case study of aftershock sequence of strong M=9.1 EQ (Sumatra-Andaman Islands, 26.12.2004) after the SF of X7.2 class (20.01.2005) demonstrated that the number of aftershocks with magnitude M≥2.5 increases more than 20 times after the SF with a delay of 7 days. For the case of the Darfield EQ (M=7.1, 04.09.2010, New Zealand) it was shown that strong SFs of class X and M probably triggered three strong aftershocks (M>5.5) with the same delay of 6 days on the Port Hills fault, which is the most sensitive to external EM impact from point of view of the fault electrical conductivity and orientation [5]. The similar result was obtained for aftershock sequence response of 7 strong EQs of Northern California to 24 strong pulsations of the horizontal component dBx of the GMF (|dBx/dt| ≥ 50 nT/min) recorded at the Fresno Observatory in the period 1991-2024. The physical mechanism of EM-EQ triggering may be connected with fluid behavior during EM impact, similarly to dynamic EQ triggering. For verification of this hypothesis a statistical analysis of seismicity was performed at three geothermal fields in Northern California (Long Valley, Coso, and Geysers) during 24 GMF strong pulsations. A statistically significant increase in regional seismicity of geothermal fields with delay of 2 to 10 days after the GMF pulsation is shown, when the daily number of EQs exceeds the average number of EQs determined for the previous 30 days, plus a threefold value of the standard deviation. This effect indicates not only the presence of an EQ triggering potential for GMF pulsations, but also the possible role of fluids in the EM triggering of EQs. An approach to obtaining additional prognostic information for short-term earthquake forecasting based on the results of reliably recorded seismicity responses to strong external EM impacts under severe space weather conditions is proposed and discussed.
The work is supported by RSF (project No. 24-27-00205).
Keywords: severe space weather, geomagnetic pulsations, electromagnetic earthquake triggering, short-term earthquake forecast

References:
1. Sorokin V.M., Yashchenko A.K., Novikov V.A., 2019. A possible mechanism of stimulation of seismic activity by ionizing radiation of solar flares. Earthquake Sciences 32(1) 26-34. https://doi.org/10.29382/eqs-2019-0026-3.
2. Sorokin, V.; Yaschenko, A.; Mushkarev, G.; Novikov, V. Telluric Currents Generated by Solar Flare Radiation: Physical Model and Numerical Estimations. Atmosphere 2023, 14, 458. https://doi.org/10.3390/atmos14030458.
3. Zeigarnik, V.A.; Bogomolov, L.M.; Novikov, V.A. Electromagnetic Earthquake Triggering: Field Observations, Laboratory Experiments, and Physical Mechanisms - A Review. Izv., Phys. Solid Earth. 2022, 58, 30–58. https://doi.org/10.1134/S1069351322010104.
4. Sorokin V., Novikov V. Possible Interrelations of Space Weather and Seismic Activity: An Implication for Earthquake Forecast. Geosciences. 2024; 14(5):116. https://doi.org/10.3390/geosciences14050116
5. Novikov, V.A., Sorokin, V.M. Electromagnetic Trigger Effects in the Ionosphere–Atmosphere–Lithosphere System and Their Possible Use for Short-Term Earthquake Forecasting. Izv., Phys. Solid Earth 60, 879–890 (2024). https://doi.org/10.1134/S1069351324700800

Biography:

Dr. Victor Novikov is a head of Laboratory of Pulsed Power Systems for Geophysics of the Joint Institute for High Temperatures of Russian Academy of Sciences (RAS), Moscow, Russia, Leading Researcher of Fedorov Institute of Applied Geophysics, Senior Researcher of Sadovsky Institute of Geosphere Dynamics of RAS and a head of experimental group at the Research Station of RAS located at the Northern Tien Shan (Kyrgyzstan). His research interests are R&D of pulsed power systems and their application for geology and geophysics, seismicity triggered by high-power electric pulses, development of physical backgrounds of earthquake control technology and earthquake short-term prediction based on electromagnetic earthquake triggering phenomena and space weather parameters.He served as a keynote and invited speaker at the national and international conferences, symposia, and workshops. He is a member of many international geophysical organizations (AGU, EGU, SSA, JpGU). Author and co-author of over 95 publications in the areas of power engineering and geophysics.Participant of the completed Russian-Chinese cooperation project "Coupling of geomagnetic field variations and deformation processes in the Earth crust" and Principal Co-Investigator of thesuccessfully completed Russian-Chinese cooperation project "Space weather and earthquakes" (2021-2022) supported by Russian Foundation for Basic Research and Natural Science Foundation of China. At present he is the Principal Investigator of the project "Computational and experimental studies of the physical mechanisms of electromagnetic triggering of earthquakes" (2024-2025) supported by Russian Science Foundation.