Geophysical research: article

O. Kozyreva1,2
V. Pilipenko1,2
1 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences
2 Geophysical Center, Russian Academy of Sciences
Journal: Geophysical research
Tome: 21
Number: 1
Year: 2020
Pages: 33-49
UDK: 550.385+550.348
DOI: 10.21455/gr2020.1-3
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Keywords: earthquake triggers, electromagnetic earthquake precursors, magnetic storms, geomagnetic pulsations
Аnnotation: Geophysicists are actively discussing the possibility of a trigger effect of solar activity and related perturbations of space weather (magnetic storms) on the earth's seismicity. We tried to test the idea of a magnetic storm and the telluric fields and currents induced by it as an earthquake trigger for a region with high seismicity and powerful magnetic activity - Alaska. The superposed epoch method (SPE) for the median values of magnetic disturbance relative to the moment of the earthquake considered the statistics of geomagnetic variations at the College station (USA) before and after shallow earthquakes in 2014-2016. The absolute values of the field perturbation |D X | and time derivative of the field | dX / dt | have been examined. No statistically significant deviations of the SPE curves were detected 10 days before the earthquake. On the other hand, the most intense geomagnetic disturbances occur during substorms, originating both on the background of a storm and during isolated events. The number of earthquakes of different classes was compared before and after the substorm onsets in a time interval of 10 hours, but no apparent change in seismicity after substorms was revealed. The obtained results show that the hypothesis of a magnetic storm and substorm as possible earthquake triggers for the Alaska region is not supported. At the same time, the possibility of the trigger action of powerful man-made electromagnetic pulses on local seismicity cannot be excluded. This paper is considered as an invitation to a joint discussion of space physicists and seismologists.