HR: 1330h
AN: U53A-05    [Abstracts]
TI: Tracking the Rupture of the Great Sumatra-Andaman Islands Earthquake With Teleseismic Arrays
AU: * Krger, F
EM: kruegerf@geo.uni-potsdam.de
AF: Institute of Geosciences University of Potsdam, Karl Liebknechtstrasse 24, Golm, 14476 Germany
AU: Ohrnberger, M
EM: mao@geo.uni-potsdam.de
AF: Institute of Geosciences University of Potsdam, Karl Liebknechtstrasse 24, Golm, 14476 Germany
AB: The waveform recordings of the Great Sumatra-Andaman Islands earthquake at different broadband networks located at teleseismic distances allowed imaging its rupture propagation in space and time by using a migration approach. The results suggest, that the rupture initiated at 3.6N latitude and 96.0E longitude being in very good agreement to the epicentral location estimated by NEIC from body-wave arrival data (lat: 3.3N, lon: 96.0E). From the epicenter, the rupture first propagated unilaterally North-northwest for about 220 s until it reached the northern tip of Sumatra. Then, the rupture turned to the North following the strike of the subduction zone before it ends after a total duration of around 430 s in the North of the Andaman Islands. Two major phases of energy release can be distinguished from the teleseismic observations which correspond to the two distinctly oriented segments of the rupture. Indications for a change in the radiation pattern are obtained from the observed variations in the energy-time release patterns at the different arrays. The inferred total length of the rupture is about 1150 km and the average rupture velocity is estimated between 2.5 km/s to 2.9 km/s. Later secondary phases limit the resolution capabilities of the method. However, using high-resolution array techniques, strong secondary phases can partly be resolved and ambiguities in the results can be reduced.
DE: 7200 SEISMOLOGY
DE: 7203 Body wave propagation
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
SC: Union [U]
MN: 2005 Joint Assembly