Dynamics of Upper-Frequency-Range Infrasonic Wave Generation in the Northwestern Part of the Sea of Japan

Abstract

The Pacific Northwest region is significantly affected by tropical cyclones, which pose a threat to humans due to strong winds and intense precipitation. Observations have shown that international meteorological agencies lower the hazard class of typhoons too early, or even stop tracking them altogether. We studied the results of in situ measurements of infrasonic microseismic oscillations in the upper frequency range, generated in the shelf area of the northwestern part of the Sea of Japan as a result of the long-term influence of strong tropical cyclones on the sea area. The measurement data were obtained using coastal laser strainmeters, which are components of the seismoacoustic hydrophysical measuring complex. The dynamics of upper-frequency-range infrasonic microseismic signals during the movement of Typhoon Chan-Hom 2015 in the Sea of Japan are shown. The same infrasonic microseismic oscillations excited by Typhoon 2022 Hinnamnor, which had no impact on the measuring station, have a difference in the width of the signal spectrum and frequency shift with maximum amplitude compared to the signals from Typhoon Chan-Hom.