Study of ULF-VLF wave propagation in the near-Earth environment for earthquake prediction

Abstract

This work presents the study on the electromagnetic wave penetration and propagation into the ionosphere in the frequency range of 100 Hz to 3 kHz and 3 kHz to 10 kHz, corresponding to the Ultra Low Frequency (ULF) and Very Low Frequency (VLF), respectively, for various types of applications including earthquake prediction. The main idea here is to investigate the efficiency of whistler/helicon wave generation in the E-region under different ionospheric conditions by solving Maxwell’s equations and incorporating ionospheric conditions through the Hall, Pedersen, and parallel conductivities. Specifically, the effect of pulse and continuous probing of the lower ionosphere with ULF-VLF signals and the generation of secondary waves and currents due to high conductivities in the E-region is studied. The characteristics and applications of the excited Helicon ULF-VLF waves are discussed. The effect of background ionospheric parameters such as the electron density and ionospheric disturbances due to pre-earthquake conditions and other natural sources including lightning discharges on the excitation and penetration of ULF-VLF waves into the E-region is investigated. The efficiency of this technique in developing a monitoring system to detect and locate seismic activities is discussed.