Seismoacoustic effects of the Hovsgol earthquake (Mw = 4.9) of December 5, 2014

Abstract

The results of study of the Hovsgol earthquake with M_w = 4.9, which occurred on December 5, 2014, in the northern part of Hovsgol Lake in Mongolia, are presented. An infrasonic signal of ~140 s long was recorded by the Tory infrasonic station for the first time for the Baikal Rift System. On the basis of the source parameters and focal mechanism of this earthquake determined, displacements in the epicentral zone of the Hovsgol earthquake are modeled. It is shown that they could not have produced an infrasonic sound. The use of acceptable values of group velocities of infrasonic waves (0.28–0.35 km/s) demonstrates that the signal source was located approximately midway between the Tory station and the epicenter of the Hovsgol earthquake, indicating it was a secondary source. Based on the data on the azimuth and arrival time of the acoustic wave at the Tory station, the location of this secondary source is determined to have been on the northern slopes of the Khamar Daban Range. The infrasonic signal formed most likely by interaction between seismic waves from the earthquake and the mountain relief.