HR: 1340h
AN: S13A-1044    [Abstracts]
TI: Fault model of the 2007 Solomon earthquake estimated from the crustal deformation survey data
AU: * Tanioka, Y
EM: tanioka@mail.sci.hokudai.ac.jp
AF: Hokkaido University, N10W8 Kita-ku, Sapporo, 060-0810, Japan
AU: Namegaya, Y
EM: yuichi.namegaya@aist.go.jp
AF: Active fault Research Center AIST, Site 7, 1-1-1 Higashi, Tsukuba, 305-8567, Japan
AU: Nishimura, Y
EM: yns@mail.sci.hokudai.ac.jp
AF: Hokkaido University, N10W8 Kita-ku, Sapporo, 060-0810, Japan
AU: Yoshinobu, T
EM: tsuji@eri.u-tokyo.ac.jp
AF: Tokyo University, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
AU: Nakamura, Y
EM: nyugo@mail.sci.hokudai.ac.jp
AF: Hokkaido University, N10W8 Kita-ku, Sapporo, 060-0810, Japan
AU: Murata, M
EM: murata@recoveryplatform.org
AF: Asian Disaster Reduction Center, 1-5-2, Wakinohama-kaigan-dori Chuo-ku, Kobe, 651- 0073, Japan
AU: Woodward, S
EM: smwoodwa@kent.edu
AF: Kent State University, Kent, Ohio, OH 44242, United States
AB: On April 1, 2007, a large earthquake occurred off the Solomon Islands along the Solomon subduction zone. The earthquake generated a large tsunami that killed more than 40 people in Gizo and Simbo Islands near the epicenter. The one day aftershock distribution showed that the source region was located in the subduction zone where the Woodlark ridge system subducted beneath the Pacific plate. Because of the subduction of the ridge, no trench exists near the plate boundary. Instead, two Islands, Simbo and Ranongga Islands, exist unusually close to the plate boundary. About two week after the earthquake, the Japanese survey team was in the Solomon Islands to conduct the coseismic deformation survey in Gizo, Simbo, Ranongga, Vella Lavella, and Kilimbangara Islands near the source area of the 2007 Solomon earthquake. A whole island of Ranongga was uplifted by the earthquake because a large area of coral flats around the island was now appeared above high tide levels. In Simbo Island, located about 20km south of Ranongga Island, we found small subsidence. In Vella Lavella Island, the most part of the island was subsided except the most southeast tip of the island. In Gizo Island, the small subsidence was found along the most part of the coast. Using those crustal deformation data, we estimated that the strike of the fault is 315 degree, the width of the fault is 35 km, the dip of the fault is about 35 degree which is much larger than a typical dip of the plate interface near a trench, the shallowest edge of the fault is located between Simbo and Renongga Islands, and the depth of the shallowest edge is less than 5km. This unusual splay fault type earthquake occurred in this area where the Woodlark ridge subducted beneath the Pacific plate.
DE: 7215 Earthquake source observations (1240)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Seismology [S]
MN: 2007 Fall Meeting