Investigation of earthquake display in EM field and ionosphere

Abstract

In this paper we present the results of our investigation of displaying of seis-mic activity in variations of both the electromagnetic (EM) field and the basic ionospheric characteristics. The 3D case is considered taking into account the effects of weak nonlinearity, dispersion and dissipation in medium, that allows us to obtain more accurate results for both the near and far zones from the earthquake epicenter. In study of the seismic response in the EM field, it is shown that a precursor arises ahead the front of seismic wave, its amplitude decreases exponentially with distance. In case of a single compression pulse, the precursor is negative, and its amplitude depends on the medium conductiv-ity and the parameters of the wave. With increasing conductivity, the amplitude of precursor increases, and its characteristic scale decreases. Regarding the response at ionospheric heights, the seismo-ionospheric post-effects have been studied, which are of great interest, in particular, for a better understanding of relationships in the system "solid Earth - atmosphere - ionosphere" and for identification of seismically caused oscillations in the spectrum of the ionospheric fluctuations, etc. The effect of the acoustic impulse caused by the Rayleigh wave on the ionosphere's neutral component near the epicenter is consid-ered, and further formation of the solitary IGWs and the TIDs, which are caused by them, at the F-layer heights in the far zone. The results obtained are in good agreement with the results of our radiophysical experiments during seismic events at the Russia Far East region.