ATMOSPHERIC-SEISMIC EFFECT OF CHELYABINSK METEOROID

Abstract

Purpose: The parameters of the shock-wave source in the atmosphere and seismic oscillations that this source caused are investigated Design/methodology/approach: The atmospheric and seismic processes caused by the passage and explosion of Chelyabinsk meteoroid on February 15, 2013 have been modelled. The model results are compared with the observation results obtained at several seismic stations. Findings: The shock-wave impact duration is shown to be equal to approximately 97 s, and the time delays of the shockwave at the sites of destruction relative to its generation time at altitudes of 23÷53 km are shown to be equal to 77÷295 s in the distance range interval of 23÷84 km. The length of the area destructed by the shock with the access pressure of no less than 0.7 kPa is determined to be equal to 125÷130 km, and its width to 16÷60 km at various parts of the meteoroid path. The regression relation between the duration of the seismic signal and the length of the seismic wave path has been determined. The characteristic scale time of seismic source impact is equal to approximately 40 s. In the 20÷50 -s period range of seismic oscillations, the dependence of the group speed on period is established. The attenuation depth of seismic waves is estimated to be approximately 10÷20 Mm in the frequency range of 0.25÷3.0 Hz, and the Earth’s crust speed to 5.7÷7.0 μm/s. Conclusions: The model and estimation results are in good agreement with the observations.

Keywords

• seismograms; seismic wave speed; trace length in the atmosphere; propagation time; destruction area parameters; seismic signal parameters; seismic signal duration
• speed and attenuation rate; earth’s crust amplitude and wave motion; earthquake magnitude and energy