ELECTROMAGNETIC EMISSION CAUSED BY THE FRACTURING OF PIEZOELECTRIC CRYSTALS WITH AN ARBITRARILY ORIENTED MOVING CRACK

Abstract

Electromagnetic emission (EME) caused by fracturing of piezoelectric effects in rocks has been studied. We have analyzed a finite size piezocrystal undergoing such mechanical stresses which cause an uniform movement of a crack. Direction of the crack movement and its front orientation have been assumed arbitrary with respect to the crystal axes. In such a case polarization currents appear with potential and vortical components, corresponding to the electric polarization currents and magnetization currents. Amplitude–frequency characteristics of the EME in long-wavelength region have been analyzed too. This effect of EME is of great importance for natural hazards including volcano eruptions and earthquakes.