Explosions and seismic phenomena based on exciting of acoustic-electromagnetic waves

Abstract

During earthquakes and strong underground explosions it is possible to observe two different effects. The first one is connected with the destruction of media, and this causes acoustic and later hybrid acoustic-electromagnetic waves in an epicenter in the atmosphere and in the ionosphere. Another one is connected with cracks in crystals of rocks, which seems more interesting, because it is possible to recognize the natural earthquakes and industrial explosions. In the first effects due to nonlinear elastic modules the acoustic waves move through the lithosphere and transform their spectra from VLF (very low frequencies ~ 1 - 10 kHz) at the depth of about 30 km into the lower part of ELF (extremely low frequencies, ~ 3 Hz - 1 kHz) on the Earth’s surface, then they pass the atmosphere and penetrate into the ionosphere. During the nonlinear acoustic passage through the atmosphere and the ionosphere, the spectrum transforms from ELF into ULF (ultra low frequencies, < 1 Hz) range. In this review article the classification of spectrum and analysis of two cases of the destruction of rocks in the lithosphere is presented. The rocks possess piezoelectric and piezomagnetic properties. In this case the electromagnetic emission is excited by the fracturing in plates of crystals. The difference of emission from piezoelectric and magnetic plates in cases of industrial explosions and natural seismic events including volcanic phenomena gives a possibility to analyze the method of its identification. The consideration is based on the model of the plate of a finite size with an uniformly moving crack

Statistical discrimination of global post-seismic ionosphere effects under geomagnetic quiet and storm conditions

“…Dependence of larger ionospheric TEC precursors (within 1 h before EQ) on larger earthquake magnitudes is reported by Heki and Enomoto (2015). According to the acoustic mechanism, the internal atmospheric gravity waves are generated both before and after the earthquakes (Hegai et al 2006;Koshevaya et al 2012). The speed of the earthquake-induced acoustic gravitational wave propagation through the ionosphere can reach 990 m/s as detected with GPS network up to the sound speed at ionospheric heights, and these effects in the ionosphere are observed at distances up to 2000 km from the hypocentre .…”

Autonomous Instrumentation for Measuring Electromagnetic Radiation from Rocks in Mine Conditions—A Functional Analysis

“…Many researchers link the piezoelectric effect to developing cracks and stress-vibrations in the rock structure [40,41]. Example relationships describing such a phenomenon are as follows [42]:…”

DWT-based methodology for detection of seismic precursors on electric field signals in Mexico

“…On the other hand, there are electrical phenomena such as electrical currents, which flow between lithosphere and ionosphere that are also related to seismic events (Kuo et al 2011;Pulinets and Davidenko 2014). Furthermore, there are atmospheric gravity waves that are generated before and after the main shock (Hegai et al 2006;Koshevaya et al 2012). They can reach speeds up to 990 m/s, generating the possibility of being detected by the GPS satellite network.…”