Seismic signatures of atmospheric disturbances in the Western Pacific as a tool for reconstruction of their dynamics

Abstract

  The wind and products of snowfalls and rainfalls touching the ground generate the seismic signals. During the decades, the study of seismic signatures of atmospheric disturbances, cyclones, was based on analysis of the ambient seismic noise in the low-frequency range which allowed identification of cyclones and location of the storm position. The methodology of monitoring of the atmospheric events using the short-period seismic signals recorded by a sensor installed at a height of about 4 km above sea level at the summit of dormant volcano Nevado de Colima is proposed. The methodology includes the indication of the seismic signatures of atmospheric disturbances on the daily helicorder displays of seismic signals with following analysis of waveforms, produced by the impact of rainfalls and snowfalls with the ground surface, and their Fourier spectral characteristics. Then, the reconstruction of the passage of the atmospheric events, based on the power spectral densities of the one-hour seismic records, which is performed mutually with the satellite observations. The methodology was applied to study the passage of hurricane Dora and its preceding tropical storm (June 2017) and the cold front system number 25 (January 2018). There were indicated the periods of actions of tropical storm, hurricane, and two stages of the cold front on the helicorder images. Then the characteristic waveforms for each period were selected. Analysis of the spectral characteristics of these waveforms demonstrated that the rainfalls, occurring during the tropical storm, hurricane and the initial stage of the cold front passage, generated the seismic signals within the frequency range between 1.0-1.8 Hz while the snowfall during the second stage of the cold front passage generated the seismic signals within the frequency range between 2.6 and 3.7 Hz. The reconstruction of dynamics of the passage of the atmospheric events based on the power spectral densities of the one-hour seismic records allowed to see the comparable intensity of tropical storm and hurricane, and two stages of the cold front. These results demonstrate a possibility for monitoring the passage of atmospheric disturbances in real time or to perform the reconstruction the dynamics of these events during past time using the short-period seismic signals recorded at the high heights.