SHARP DECREASES IN THE DENSITY OF THE SPORADIC ES LAYER IN THE IONOSPHERE AS AN EARTHQUAKE PRECURSOR

Abstract

Seismically generated ionospheric phenomena have been discussed in several publications; the primary focus has been on the F layer. Effects in the E layer have been reported, but there has been no detailed analysis of them. In addition, no convenient parameters that can be used to identify phenomena of seismic origin in the Es layer have previously been identified. In the present paper we identify a new and convenient parameter which characterizes the fine structure of the diurnal variation in the critical frequency fbEs. This parameter is rather sensitive to electromagnetic processes taking place in earthquake preparation zones. In developing a method of identifying seismically generated phenomena, we considered the implications of our earlier model of seismic-ionospheric interaction. This model postulates that during earthquake preparation large-scale intermittent charge separation occurs in the crust.