Telluric Currents Generated by Solar Flare Radiation: Physical Model and Numerical Estimations

Abstract

The current studies of solar-terrestrial relations and possible impact of space weather on the seismic activity are based on statistical analysis without detailed consideration of possible physical mechanism that results in fuzzy and contradictory conclusions. We propose to consider a hypothesis of electromagnetic earthquake triggering by a sharp rise of telluric currents in lithosphere including crust faults due to interaction of solar flare X-ray radiation with ionosphere-atmosphere-lithosphere system resulted in a rise of telluric currents in the crust faults. This hypothesis is based on field and laboratory experiments carried out in Russia within the last forty years and clearly demonstrated a possibility of earthquake triggering by electric current injected into the fault. We developed a mathematical model and computer code for numerical estimations of telluric currents generated by solar flare radiations. The obtained numerical results demonstrate that solar flares can cause variations in the density of telluric currents in the crust faults, comparable to the current densities generated in the Earth’s crust by artificial pulsed power sources capable to trigger earthquakes. Consequently, the triggering of seismic events is possible not only by artificial sources of electric current, but also by ionospheric disturbances caused by strong solar flares.