Akademik Veri Yönetim Sistemi
GPS SOLUTIONS, cilt.26, sa.4, 2022 (SCI-Expanded)
We study the impact of the severe equatorial earthquakes on the ionospheric Equatorial Ionization Anomaly (EIA) to check the variations in the shape of electron concentrations along the earthquake longitudes as the possible precursors to the earthquakes by considering a case study of a strong M-w 7.3 seismic event from Honduras occurred in 2009. We have observed sharp increments in the atmospheric chemical potential and surface air temperature time series along with an abrupt decrease in the relative humidity simultaneously about 5-8 days before the impending earthquake indicating the procreation of the air ionization due to increased radon activity around the earthquake's epicenter. We further investigated the ionospheric conditions by estimating the total electron content (TEC) from 6 IGS stations. The results suggested that the 2 IGS stations operating within the earthquake preparation area (EPA) showed prominent TEC enhancements about 5 days before the impending earthquake, consistent with the seismic atmospheric circulations. The other 3 IGS stations, operating outside the EPA, did not show any perturbation. These TEC variations are quantified based on two different methods: (1) running interquartile method and (2) method of cognitive recognition (applied on station BOGT). Moreover, the TEC and electron density profiles, retrieved from station BOGT and the ISL probe of the DEMETER satellite, respectively, revealed that the local TEC enhancements further dispersed toward the magnetic equator at higher altitudes by developing an enormous two-hump-like EIA structure near the epicentral longitude that verifies the generation of the seismogenic electric field through air ionization. We believe that our multi-precursory analysis is another step forward in comprehending the seismic lithosphere-ionosphere interactions.