Tectonics in the Eastern Asia inferred from GPS observations

Shin'ichi MIYAZAKI, Shigeru MATSUZAKA, Kosuke HEKI, Masaru KAIDZU, Yuki KUROISHI, Masaki MURAKAMI, Tetsuro IMAKIIRE, Takashi TADA, Koh NITTA, Hiroyuki NAKAGAWA, Akifusa ITABASHI, Masao KARASAWA, Osamu OOTAKI, Norihiko ISHIKAWA, Masayoshi ISHIMOTO, Hiroaki TAKAHASHI, Minoru KASAHARA, and Ki-Dok An


The crustal velocity field in Eastern Asia is investigated. We first analyze continuous GPS data for Korea,Far East Russia,China, and southwest Japan.Velocities are found to have an apparent eastward component relative to the stable interior of the Eurasian plate,and this eastward motion is fairly rigid in the region that includes Suwon,and Taejon (Korea),Xian (China),and Vladivostok and Yuzhno-Sakhalinsk (Russia). This area corresponds to the Amurian plate and its Euler vector with respect to the Eurasian plate is estimated to be (21.7°,108.0°, - 0.092°/Ma). This result predicts that the convergence rate at the eastern margin of the Sea of Japan is about 16 ~ 18 mm/yr as the Amurian - North American relative plate motion. The result also implies that the convergence rate at the Nankai Trough is 60 ~ 65 mm/yr and the resultant deformation by this plate interaction reaches the northernmost part of the Chugoku district. The crustal velocity field of southwest Japan relative to the Amurian plate gives its intraplate deformation. We show that the obtained velocity field could be decomposed into an elastic loading by subduction and a collision-related deformation.


1. Introduction
2. The Amurian plate and its motion
3. Data and analysis
4. Observation equation
5. Results
  5. 1 Euler vector for the Amurian plate
  5. 2 Kinematics of the Amurian plate relative to its adjacent areas
6. Discussion
  6. 1 Baikal Rift and the Stanovoi Range
  6. 2 Eastern margin of the Japan Sea and Sakhalin
  6. 3 Nankai Trough
  6. 4 Implication for the velocity field of southwest Japan
7. Conclusion