Analytical Model of a Seismogenic Electric Field According to Data of Measurements in the Surface Layer of the Midlatitude Atmosphere and Calculation of Its Magnitude at the Ionospheric Level

Abstract

Perturbations of the vertical component of an electric field of seismogenic origin near the Earth’s surface prior to some earthquakes are modeled analytically based on data from measurements in the surface layer of the atmosphere at midlatitudes, and the field’s magnitude at the ionospheric level is calculated with allowance for the inclination of geomagnetic lines of force. An analytical approximation of the seismogenic perturbation of the vertical component of the electric field on the Earth’s surface is obtained. The approximation adequately describes the data from those measurements. It is shown that, ~3.5 h before the earthquake on March 20, 2008, in the border region of the Chinese provinces of Xinjiang and Xizang, which had a with a magnitude of M = 7.2, the detection of a quasi-static electric field with a seismogenic nature and a magnitude of 0.44 to 0.88 mV/m can be hypothetically expected over the epicentral area in the ionosphere; the field is perpendicular to magnetic field lines.