Microseismic oscillations as an indicator of tropical cyclones

Abstract

   The paper presents the results of recording microseismic oscillations in the frequency range of infrasonic waves performed during the periods of active influence of tropical cyclones on the water area of the Sea of Japan. The data were obtained by a coastal laser-interference measuring complex consisting of a two-axis laser strainmeter and a laser nanobarograph. A case study using remote sensing data shows that the world meteorological agencies stopped tracking the typhoon too early, while the cyclone retains its vortex structure and energy characteristics. The dynamics of changes in the characteristics of infrasound microseismic oscillations, which depend on the trajectory of typhoons and the duration of their impact on the sea area, is shown. Generalised results are given for some groups of typhoons having similar trajectories of movement, as a result of which the maximum amplitudes of microseismic infrasonic oscillations are manifested at different frequencies. During the passage of a category 5 typhoon in 2022, a microseismic signal formed by the interaction of the atmospheric vortex in the rear part of the cyclone with the field of quicksand waves was registered near the measuring site. As a result of registration by ground-based remote sensing methods of certain characteristics of microseismic signals generated during the passage of typhoons, it is possible to use the information to determine the parameters of tropical cyclone movement.