Remote Response of an Electric Field and Atmospheric Current to Strong Earthquakes

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Remote Response of an Electric Field and Atmospheric Current to Strong Earthquakes S. A. Riabovaa,* and A. A. Spivaka Presented by Academician V.V. Adushkin July 13, 2020 Received July 15, 2020; revised August 26, 2020; accepted August 27, 2020

Abstract—The vertical component of the electric field strength and atmospheric current variations accompanying strong earthquakes with a magnitude of more than six are analyzed on the basis of instrumental observations carried out at the Mikhnevo Geophysical Observatory and at the Center for Geophysical Monitoring in Moscow (Sadovsky Institute of Geosphere Dynamics, Russian Academy of Sciences). It is shown that the strong earthquakes cause alternating sign–time variations of the electric field or its baylike variations of positive or negative sign at significant distances from the earthquake source. In the same time, earthquakes cause variations in the atmospheric current in the form of an increase in it or alternating sign–time variations of the averaged amplitude. The present results supplement the corresponding database and may be of interest in improving the known and developing new models of the effect of earthquakes on the environment and their verification. Keywords: earthquake, variations of the electric field, atmospheric current, vertical component of the electric field strength DOI: 10.1134/S1028334X20110124

Earthquakes as catastrophic phenomena remain insufficiently studied and hardly predictable, despite the technical progress achieved and the expanded networks recording seismic activity. Dynamic manifestations of earthquakes and the accompanying geophysical effects are presently among the most important objects under study in the field of Earth Sciences. Recent research convincingly indicates a relationship between processes in the lithosphere that accompany earthquake preparation and development and disturbances in the near-surface atmosphere and in the ionosphere [1–3]. In particular, it has been shown on the basis of analysis of the data from the monitoring of near-surface envelopes of the Earth and the satellite data that electromagnetic disturbances occur in a broad spectral interval at the final stage of earthquake preparation and in the periods of the mainshock and aftershock activity [4, 5]. Studies of this kind are not only of fundamental importance, but also of applied value in that they can help improve and develop new approaches for earthquake forecasting [3, 6]. a Sadovsky

Institute of Geosphere Dynamics, Russian Academy of Sciences, Moscow, 119334 Russia *e-mail: [email protected]

It should be noted that the proposed mechanisms of electrical anomalies induced by seismic events do not allow for abrupt change in the time variations in electric field strength, which has been revealed in many cases immediately before an earthquake and, especially, in the period of the mainshock [7, 8]. In this respect, the instrumental studies aimed at revealing the response of the atmospheric electric field to earthquakes remain topical. The present commun