文章基本信息

标题：Seismotectonic implications of the Kyushu-Palau ridge subducting beneath the westernmost Nankai forearc
其他标题：Seismotectonic implications of the Kyushu-Palau ridge subducting beneath the westernmost Nankai forearc
本地全文：下载
作者：Jin-Oh Park ; Takane Hori ; Yoshiyuki Kaneda 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2009
卷号：61
期号：8
页码：1013-1018
DOI：10.1186/BF03352951
出版社：Springer Verlag
摘要：The Kyushu-Palau ridge, a remnant arc on the Philippine Sea Plate, subducts beneath the Eurasian Plate along the westernmost part of the Nankai Trough. A seismic reflection profile on strike line images the ∼70-km-wide Kyushu-Palau ridge where it subducts beneath the toe of the forearc accretionary wedge. The geomagnetic anomaly signature, seafloor topographic features, wide-angle refraction data, and on-land geomorphologic evidence enable us to trace the forearc extension of the subducted ridge up to the east Kyushu. The subducted Kyushu-Palau ridge with excess mass may be relatively buoyant, and thus is more likely to resist subduction upon collision with the overriding plate at depth, leading us to speculate that there is locally large tectonic stress at the contact zone between the subducted ridge and base of the overriding plate. The large stress zone is marked by historic thrust-type intermediate-class (magnitude 6 or 7) earthquakes. The flank regions of the subducted buoyant Kyushu-Palau ridge are more likely to tear and result in slab fracturing when the ridge subducts deeper. We propose that the subducted Kyushu-Palau ridge may serve not only as a seismic asperity at depth but also produce the slab fracture as a seismic barrier inhibiting the rupture propagation of the adjacent megathrust earthquakes in the Hyuga segment.
关键词：Kyushu-Palau ridge ;Nankai Trough ;reflection profile ;asperity ;barrier