T-phase from the big Sumatra earthquake (2004/12/26)
2004年苏门答腊大地震激发的T-波

Tertiary(T-) waves are seismically generated acoustic waves that can propagate over great distances in the SOund Fixing And Ranging(SOFAR) channel.On 2004/12/26,big Sumatra earthquake(Mw=9.3) occurs at the Sumatra island.A huge tsunami excited by the energy from the big Sumatra earthquake causes a great lose,thus a lot of scientists from all over the world pay a lot attention to such big Sumatra earthquake.In this paper,we report the signal of the big earthquake at island stations(PALK) and(DGAR),and extract the clear T-phase by high pass filter.At the same time,in frequency domain,we obtain the relationship between the spectrogram of the T-phase and the travel time.After the analysis,In addition we obtain the duration of the this Sumatra earthquake is about 500s,including two big energy extracting processes,the time difference between the two big processes is about from 80s to 100s.The study from T-phase will provide us an independent way to study the earthquake,especially the earthquakes occurring at the ocean bottom and subduction zone region.