HR: 0800h
AN: G51A-0147    [Abstracts]
TI: Seafloor Crustal Deformation Close to the Nankai Trough, Japan
AU: * Tadokoro, K
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Sugimoto, S
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Watanabe, T
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Okuda, T
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Muto, D
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Kimoto, A
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Ando, M
AF: Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
AU: Sayanagi, K
AF: Tokai University, 3-20-1 Orito, Shimizu, Shizuoka, 424-8610, Japan
AU: Kuno, M
AF: Mie Prefectural Science and Technology Promotion Center, 3564-3 Hamajima, Shima, 517-0404, Japan
AB: \ \ \ The Nankai Trough is one of the active plate boundaries in the world. Major subduction earthquakes, Nankai and Tonankai earthquakes, repeatedly occur with intervals of 100-150 years at the Nankai Trough. The last large earthquakes occurred in 1944 and 1946. Therefore, the 50-years probabilities of next major earthquakes are 80- 90 %. It is necessary to monitor crustal deformation above the source regions for the sake of earthquake prediction and disaster prevention. The source regions of the earthquakes are located beneath the sea bottom, to the south of the Japan Islands. \par \ \ \ One of the useful tools to monitor seafloor crustal deformation is the observation system composed of the acoustic ranging and kinematic GPS positioning techniques. We have installed seafloor benchmarks for acoustic ranging at the Nankai Trough region. We repeatedly observed at the two sites from 2004. The result of the repeated observation shows that the repeatability of the measurement is +/- 2-3 cm for the horizontal components. Also we detect crustal deformation related to plate convergence using our system. The velocity vectors derived from our repeated observation are (7.0 cm/yr, N78W) and (5.2 cm/yr, N87W), which is consistent to the on-land continuous observations.\par \ \ \ This study is promoted by Ministry of Education, Culture, Sports, Science and Technology, Japan. We are grateful to the captains and crews of Research Vessels, "Asama"and "Hokuto."
DE: 1209 Tectonic deformation (6924)
DE: 1222 Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959)
DE: 1294 Instruments and techniques
DE: 7240 Subduction zones (1207, 1219, 1240)
SC: Geodesy [G]
MN: 2007 Fall Meeting