• J E THOMAS

      Articles written in Journal of Earth System Science

    • Electron temperature and ion density perturbations prior to the M6.8 Eastern Honshu, Japan earthquake of July 23, 2008

      J E THOMAS A M EKANEM N J GEORGE A E AKPAN

      More Details Abstract Fulltext PDF

      The Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) microsatellite-monitored data (IAP and ISL) were employed in investigating pre- (30 days) and post- (10 days) perturbations in ionospheric parameters associated with the M6.8 Eastern Honshu (Japan) earthquake (EQ) of July 23, 2008. The results constrained by synchronously monitoring geomagnetic indices data: Kernnifzer digit and disturbance storm time (Dst), revealed strong seismic event-induced disturbances three weeks to 5 days before the seismic event. The geomagnetic indices data were used in filtering normal geomagnetic disturbances from the seismic counterparts, thereby constraining the interpretations. The total ion density measured in per cubic centimeter (cm$^{-3}$) recorded variations of 7.90, 4.51, and 5.92 on days-20, -19, and -16, respectively, from the earthquake day during the night time half orbit observations. Contemporaneously, perturbations of 8.81 were observed for electron temperature measured in Kelvin (K) five days afore the earthquake. The geomagnetically quiet state of the ionosphere during the pre-seismic days suggests that the observed disturbances are seismogenic. More researches should be encouraged in this area to deepen their applications in earthquake monitoring and prediction.

      $\bf{Highlights}$

      $\bullet$ Use of DEMETER data for earthquake prediction.

      $\bullet$ Ionospheric plasma parameters used in detecting seismo-genic induced perturbations.

      $\bullet$ Quiet atmospheric geomagnetic perturbations before the earthquake is seismogenically induced.

      $\bullet$ Seismo-genic anomalies are promising for short-term earthquake prediction.

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