Acoustic Effects of Strong Earthquakes

The results of instrumental observations of acoustic effects from a number of strong earthquakes in Albania, Greece, Iran, and Turkey with magnitudes from 5.1 to 6.9 are presented. The observations were carried out at three sites-at the Geophysical observatory "Mikhnevo" (54.94 degrees N; 37.73 degrees E), at the Center for Geophysical Monitoring in Moscow (CGM) (55.70 degrees N; 37.57 degrees E) of the Sadovsky Institute of Geosphere Dynamics of the Russian Academy of Sciences, and at the observation site in Zvenigorod, Moscow region (55.69 degrees N; 36.77 degrees E). This observation geometry provided the directions to the sources of acoustic perturbations. It is shown that earthquakes with the sources located at distances from similar to 1845 to similar to 2815 km from recording points cause perturbations in the atmosphere in the form of acoustic oscillations in infrasound range propagating in the stratospheric waveguide and in the form of acoustic oscillations caused by seismic waves. The characteristic periods of the acoustic signals caused by the earthquakes are presented. The energies of the acoustic source and the earthquake are estimated from the spectral characteristics of infrasonic signals propagating in the stratospheric waveguide.