کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4693021 | 1636834 | 2011 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Back-arc spreading of the northern Izu–Ogasawara (Bonin) Islands arc clarified by GPS data Back-arc spreading of the northern Izu–Ogasawara (Bonin) Islands arc clarified by GPS data](/preview/png/4693021.png)
We examined GPS data in the northwestern Pacific region, which includes the Izu–Ogasawara (Bonin)–Mariana (IBM) arc and the Japan arc. GPS velocity vectors on the Izu Islands, including Hachijo-jima and Aoga-shima, show systematic eastward movement deviating from that predicted by the rigid rotation of the Philippine Sea plate; this deviation supports the active back-arc spreading model suggested by previous geological studies. The results of a statistical F-test analysis with 99% confidence level showed that the forearc of the Izu Islands arc has an independent motion with respect to the rigid part of the Philippine Sea plate. We developed a kinematic block–fault model to estimate both rigid rotations of crustal blocks and elastic deformation due to locked faults on the block boundaries. The model suggests that the back-arc opening rate along the Izu back-arc rift zone ranges from 2 mm/yr at its southern end to 9 mm/yr near Miyake-jima, its northern end. It also predicts 23–28 mm/yr of relative motion along the Sagami Trough in the direction of ~ N25°W, where the Izu forearc subducts beneath central Japan. The orientation of this motion is supported by slip vectors of recent medium-size earthquakes, repeated slow-slip events, and the 1923 M = 7.9 Kanto earthquake.
► We examine GPS data in the Izu–Ogasawara–Mariana arc and the Japan arc.
► The Izu Islands arc has an independent motion on the Philippine Sea plate.
► The rate of the Izu back-arc opening increases from 2 to 9 mm/yr toward north.
Journal: Tectonophysics - Volume 512, Issues 1–4, 20 November 2011, Pages 60–67