Recording typhoons’ infrasonic disturbances by laser strainmeters
In the paper, the field studies of powerful infrasonic disturbances in the range of "voice of the sea" (7 – 9 Hz) caused by tropical cyclones (typhoons) in the southeastern region of the Far Eastern Federal District (Russia) and the water area of the Sea of Japan have been presented. Event monitoring was carried out using the laser-interference measuring complex located permanently in the South of Primorski Krai. The dynamic spectrograms of the observable events were analyzed and their connection with various meteorological phenomena, such as wind and sea waves, was followed. Using the satellite data, a connection between the distribution of the area of typhoons influence in the region and the observed infrasound excitation was found. The conclusions were drawn regarding the correlation between the exhibition of the "voice of the sea" microseisms and the initiation of primary and secondary microseisms, as well as the one between the "voice of the sea" microseisms’ disappearance and the corresponding end of primary microseisms. No dependence of the signal level on the wind speed in the area of the measuring range location was established.