Characteristics of two-azimuth seismic ionospheric disturbances
following the 2020 Jamaica earthquake from GPS observations
Earthquakes often occur and may induce the ionospheric disturbance. In
order to understand the generation and process of the earthquake, the
seismic ionospheric disturbance (SID) may provide insights on
earthquakes. In this paper, the seismic ionospheric disturbances
following the Mw 7.7 Jamaica earthquake on 28 January 2020 are detected
after 12min of the main shock by the dual-frequency GPS measurements.
Two disturbances in different azimuths are significantly found by
satellite PRN26 and PRN03. The one is located at the southwest area in
the range of 700-800km away from the epicenter while the other is
located at the southeast area in the range of 200-450km. The propagation
speeds of the two disturbances are 2.53km/s and 2.57km/s respectively.
Furthermore, we estimated the detailed characteristics of SID (primarily
the amplitude, elevation and azimuth angle, waveform and frequency) and
discussed the generation and motion process of the ionospheric
disturbance with seismograph, focal mechanism and magnetic field. The
relation among SID, Rayleigh wave and focal mechanism are interpreted.
Furthermore, the azimuthal asymmetry of SID amplitude and the appearance
of the inverted N-shape waveform observed by satellite PRN26 are the
main distinctions in the two disturbances as a result. Finally, the up
propagating secondary acoustic wave triggered by the seismic Rayleigh
wave from the strike-slip earthquake is the main source of the two