Theoretical models of seismic electromagnetic radiation based on piezoelectric effects

Abstract

To explain the phenomenon of the electromagnetic disturbance that occurs prior to earthquakes, we conducted a theoretical study of the relationship between the characteristics of electromagnetic disturbances before earthquakes and the seismogenic stress field generated by piezoelectric effects. Seismic wave field model of natural seismic excitation was studied from the perspective of the piezoelectric effect, and the electrical model developed described the evolution of the pre-earthquake electromagnetic field coupled with the seismic wave field. The relationship among the electromagnetic radiation intensity, the parameters of the geologic medium and the propagation distance in the coupling was also investigated. One of the main mechanisms underlying electromagnetic anomalies in certain bands during a strong earthquake was the release of an electromagnetic wave generated by the transmission of a stress wave in rock containing piezoelectric crystals. The change in the pre-earthquake electromagnetic field was affected by its interaction with the seismic wave field, the properties of the medium of the observation points and the distance from the epicentre. Present study suggest that to avoid great uncertainty, analyses of seismic observations should be combined with background information, including a comparison between electrical measurement results and geophysical data.