Anomaly in high-frequency geoacoustic emission as a close earthquake precursor

Abstract

One of the possible earthquake precursor mechanisms, namely, acoustic emission, is discussed. The phenomenon of acoustic emission consists in the emission of acoustic pulses due to the formation of microfaults and cracks that precede fracture of objects, rock collapse in mines, earthquakes, etc. By the example of the geoacoustic emission observation on the Kamchatka Peninsula in the area of the Avachinskaya Bay and by the analysis of anomalies of this emission that accompany major seismic events, it is shown that anomalous geoacoustic noise is generated by the stress produced in the medium prior to these events. The high-frequency range (4–11 kHz) is most informative for the observation of geoacoustic noise caused by the crack formation processes.