Seismo-ionospheric effects associated with 'Chelyabinsk' meteorite during the first 25 minutes after its fall

TL;DR

This study observed ionospheric irregularities elongated with Earth's magnetic field following the Chelyabinsk meteorite fall, linking their growth to acoustic waves generated by seismic activity, using radar and seismic data analysis.

Contribution

It provides the first experimental evidence of ionospheric irregularities growth linked to a meteorite event and models their connection to seismic and acoustic phenomena.

Findings

Detection of irregularities 40 minutes before meteor fall

Sharp increase in Doppler shift 9-15 minutes after fall

Irregularities growth associated with seismic acoustic waves

Abstract

This paper presents the properties of ionospheric irregularities elongated with Earth magnetic field during the first 25 minutes after the fall of the meteorite 'Chelyabinsk' experimentally observed with EKB radar of Russian segment of the SuperDARN. It is shown that 40 minutes before meteor fall the EKB radar started to observe powerful scattering from irregularities elongated with the Earth magnetic field in the F-layer. Scattering was observed for 80 minutes and stopped 40 minutes after the meteorite fall. During 9-15 minutes after the meteorite fall at ranges 400-1200 km from the explosion site a changes were observed in the spectral and amplitude characteristics of the scattered signal. This features were the sharp increase in the Doppler frequency shift of the scattered signal corresponding to the Doppler velocities about 600 m/s and the sharp increase of the scattered signal amplitude. This allows us to conclude that we detected the growth of small-scale ionospheric irregularities elongated with the Earth magnetic field at E-layer heights. Joint analysis with the seismic data and numerical modeling shows that the observed effect is connected with the passage of secondary acoustic front formed by supersonic seismic ground wave from the 'Chelyabinsk' meteorite. As a possible explanation the growth of elongated ionospheric irregularities may be caused by the passage of the high-speed acoustic wave in the ionosphere in the presence of high enough background electric field.