Ionospheric Precursors of December 26, 2004 Sumatran Earthquake As Seen From GPS Data

Ionospheric Precursors of Sumatran Earthquake from GPS Data.
Ionospheric Precursors of December 26, 2004 Sumatran Earthquake As Seen From GPS Data


Buldan Muslim, Hasanuddin Z. Abidin, Wedyanto Kuntjoro, The Houw Liong, Asnawi

(ITB-LAPAN)

Sumatran GPS Array (SUGAR) data have been used to study ionospheric precursors of December 26, 2004 earthquake at Aceh, Sumatran Island, Indonesia. We use GPS signal carrier phase and pseudorange code observation derive daily vertical total electron content (TEC).

Cross-correlation analysis of daily TEC from GPS station inside seismic zone with TEC from GPS station outside seismic zone from 21-31 December shown that several days before earthquake, their mutual correlations are significantly decrease. It can be interpretated that seismic activity near epicenter affect ionospheric variability. Remarkably, on December 24, 2007, the cross-correlation of COCO site to SUGAR were to be the lowest value of each, while COCO-BAKO cross-correlation was not decreasing.

Statistically, it have proven that several days before the seismic shock the level ionospheric variability increases at station closest to the epicenter, a fact which can be regarded as precursory phenomenon. By development of GPS observation around the world rapidly, ionospheric precursors from GPS observation around the world rapidly, ionospheric precursors from GPS data can be combined with other precursors so will be potential in the future for requirements of short term prediction of earthquake.