- - - School of Aerospace Engineering, Universiti Sains Malaysia Engineering Campus
- - - School of Physics,Universiti Sains Malaysia
- - - School of Physics,Universiti Sains Malaysia

This paper describes the observation and analysis of vertical electron density before major earthquake above the Sumatra-Malaysia region during Indian Ocean major earthquake in ۲۰۰۴ in Aceh, Sumatra. The electron density profile in E-layer of ionosphere a few days before earthquake and a few hours after earthquake have been observed using the data from the CHAMP satellite. The data obtained from the CHAMP satellite based on GPS radio occultation technique, starting from ۲۱st Dec, ۲۰۰۴ until ۲۷th Dec, ۲۰۰۴, between ۹۰ - ۱۲۰ km altitude ranges. It is shown that significant anomaly can be detected as early as ۳ days before the major earthquake above the preparation zone of earthquake epicentre through significant disturbances of the electron concentration in the ionosphere. In addition, the electron density in the ionosphere above the earthquake epicentre is observed to be very high during ۸ hours before earthquake occurred. After a day of the earthquake occurrence, it is observed that the electron density decreases and the ionospheric region become more stable.

earthquake, CHAMP satellite, Ionosphere, electron density