HR: 0800h
AN: U11A-0815    [Abstracts]
TI: A postseismic deformation following 2004 Sumatra-Andaman earthquake based on continuous GPS data in northern Sumatra region
AU: * OHTA, Y
EM: oota@eps.nagoya-u.ac.jp
AF: Graduate School of Environmental Studies, Nagoya University, Furo-cho, Tikusa-ku, Nagoya, 464-8602 Japan
AU: Meilano, I
EM: irwan@eps.nagoya-u.ac.jp
AF: Graduate School of Environmental Studies, Nagoya University, Furo-cho, Tikusa-ku, Nagoya, 464-8602 Japan
AU: Ito, T
EM: take@seis.nagoya-u.ac.jp
AF: Graduate School of Environmental Studies, Nagoya University, Furo-cho, Tikusa-ku, Nagoya, 464-8602 Japan
AU: Kimata, F
EM: kimata@seis.nagoya-u.ac.jp
AF: Graduate School of Environmental Studies, Nagoya University, Furo-cho, Tikusa-ku, Nagoya, 464-8602 Japan
AU: Tabei, T
EM: tabei@cc.kochi-u.ac.jp
AF: Department of Natural Environmental Science, Faculty of Science, Kochi University, 2-5-1,Akebono-cho, Kochi, 780-8520 Japan
AU: Sugiyanto, D
EM: didiksg2000@yahoo.com
AF: Department of Physics, Faculty of Natural Science, Syiah Kuala University, Banda Aceh, Banda Aceh, 23111 Indonesia
AB: To detect the postseismic deformation following the 2004 Sumatra-Andaman earthquake, we have repeated the continuous GPS measurements in Banda Aceh, northern Sumatra, Indonesia since 10th February 2005. A ground deformation of 18.9+-0.8cm toward south, 18.1+-0.5cm toward west and 1.8+-2.3cm uplift is detected until 15th July. As the direction of the deformation is toward Sunda trench and it is the same as the direction of the co-seismic deformation observed at Banda Aceh, a southwestward displacement of 26 cm is postseismic displacement following the 2004 Sumatra-Andaman earthquake. The Sumatra GPS Array (SUGAR) network continuous GPS sites also show large displacement by postseismic deformation. Though, several sites of SUGAR network sites were displaced by coseismic and postseismic of 2005 March Nias earthquake (Mw 8.7). For elimination of effect of Nias earthquake, we estimated slip distribution of coseismic and postseismic (afterslip) by geodetic inversion method based on the SUGAR network GPS data. Then we inverted GPS displacements to infer the slip distribution, amount of maximum slip reaches 13m were found beneath Nias islands at the depth of 30km. In contrast, estimated afterslip distribution located shallower part of rupture area at the depth of around 10km. Finally, we subtracted a model displacement (coseismic +afterslip) of Nias earthquake from the time series in each GPS sites. After subtracting the effect of Nias earthquake from the observed displacements, the GPS time series should include only the effect of postseismic deformation caused by 2004 Sumatra-Andaman earthquake. Based on this GPS time series, we construct model of postseismic displacement in the northern Sumatra region.
DE: 1709 Geodesy (1299)
SC: Union [U]
MN: Fall Meeting 2005