Ionospheric TEC response over Simeulue earthquake of 28 March 2005

Study of earthquake prediction, association between seismic activity and ionospheric, has been sought for many years. This study reports on the variability of the Total Electron Content (TEC) during the 28 March 2005 Simeulue, North Sumatra earthquake (epicentre:2.074°N, 97.013°E) which measured at 8.6 on the Richter scale. The ionospheric TEC near North Sumatra between 21 March to 2 April was calculated using Global Positioning System (GPS) receiver over three nearest stations to the epicenter. The IONosphere Map EXchange Format (IONEX) GPS data for 13 days period were obtained from the basis of regular GPS observation, Center for Orbit Determination in Europe (CODE) in consortium with the Federal Office of Topography. Work showed a good agreement with the existence of earthquake precursors. TEC variability was detected significantly decreasing about 7.2 TECU comparing with the last three day of highest maximum value of the day, two days before occurrence on quiet days period.