Abstract

ZOBIN, Vyacheslav M.. Seismic signatures of atmospheric disturbances as a tool for reconstruction of their dynamics. Geofís. Intl [online]. 2021, vol.60, n.4, pp.333-356.  Epub Jan 31, 2022. ISSN 2954-436X.  https://doi.org/10.22201/igeof.00167169p.2021.60.4.2124.

The wind and products of snowfalls and rainfalls touching the ground generate seismic signals. During decades, the study of seismic signatures of atmospheric disturbances, cyclones, was based on analysis of the ambient seismic noise in the low-frequency range allowing the identification of cyclones and location of the storm position. The methodology monitoring the atmospheric events using short-period seismic signals recorded by a sensor installed at an altitude of about 4 km above sea level at the summit of dormant volcano Nevado de Colima is proposed. The methodology includes the identification 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 tracks of the atmospheric events, based on the power spectral densities of the one-hour seismic records, is performed mutually with the satellite observations. The methodology was applied to study the tracks 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 tracks, 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 tracks generated the seismic signals within the frequency range between 2.6 and 3.7 Hz. The comparison of the tracks of the atmospheric events and 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 the possibility to monitor the tracks of atmospheric disturbances in real time or to perform the reconstruction of the dynamics of these events during past time using the short-period seismic signals recorded at the high altitudes.

Keywords : seismic signal; tropical storm; hurricane; cold front; rainfall and snowfall.