The propagation speed of travelling ionospheric disturbance (TID) in ionosphere and vertical gravity wave caused by Sumatra–Andaman tsunami on December 26, 2004

Research aimed at seeing the characteristic of ionospheric disturbance due to the effect of Sumatra–Andaman tsunami on December 26, 2004 have been conducted. The purpose of the study was to examine the TID speed arising from the tsunami. The study was conducted using total electron content (TEC) data from GPS satellites recorded by some GPS monitoring stations around the Indian Ocean. The GPS data is extracted to obtain a differential value of TEC (dTEC), and the value is then plotted against time. For tsunami information/data we used tsunami modelling simulations (in form of video). The results obtained indicate the TID speed related to the speed of the tsunami. The average speed of tsunami in open ocean calculated here amounted to 804.2 km/h, while the average speed of displacement of TID was about 669.9 km/h. The difference in speed between the tsunami and TID was due to the wave, at first, propagate vertically from the sea surface to the ionosphere to produce TID. From the data, the average travel time from the sea surface to the ionosphere of 0.56 hours, hence the average velocity of the vertical propagation was about 625 km/h.