Pelagic smectite as an important factor in tsunamigenic slip along the Japan Trench
Pelagic smectite as an important factor in tsunamigenic slip along the Japan Trench
复制标题
远洋蒙皂石是日本海沟海啸滑移的重要因素
作者：
Kameda;J.;Shimizu;M.;Ujiie;K.;Hirose;T.;Ikari;M.;Mori;J.;Oohashi;K.;and Kimura;G.
2011年东北冲地震（Mw9.0）期间，俯冲界面浅层的巨大滑移导致日本本州东北海岸沿着发生巨大海啸。为了阐明这种海啸滑动的机制，在地震发生一年后进行了综合大洋钻探计划第343次考察（日本海沟快速钻探项目，JFAST），并成功地恢复了构成活动板块边界断层的岩石。我们的矿物学分析，使用X射线衍射显示，浅部分的断层带，造成地震是显着富集蒙脱石相比，周围的沉积物，这可能是密切相关的海啸浅断层。为了进行比较，我们还分析了传入的沉积物的矿物学特征，就在俯冲之前，在日本海沟（站点436，深海钻探项目腿56）的外部上升恢复，并发现了一个特征的蒙脱石丰富的层位在最上层的1.55米的远洋粘土层。这一层位应该是机械薄弱，并将成为未来的板块边界故障，在JFAST核心观察。富含蒙脱石的矿床广泛分布在西北太平洋，因此可能会在日本海沟板块边界的广大地区发生地震时增强大规模浅层滑动的条件，这将导致该地区发生大海啸。
The very large slip on the shallow portion of the subduction interface during the 2011 Tohoku-oki earthquake (M w 9.0) caused a huge tsunami along the northeast coast of Honshu, Japan. In order to elucidate the mechanics of such tsunamigenic slip, the Integrated Ocean Drilling Program Expedition 343 (Japan Trench Fast Drilling Project, JFAST), was carried out one year after the earthquake and succeeded in recovering rocks constituting the active plate boundary fault. Our mineralogical analyses using X-ray diffraction reveal that the shallow portion of the fault zone that caused the earthquake is significantly enriched in smectite compared to the surrounding sediments, which may be intimately linked to the tsunamigenic shallow faulting. For comparison, we also analyzed mineralogical features of incoming sediments just prior to subduction, recovered on the outer rise of the Japan Trench (Site 436, Deep Sea Drilling Project Leg 56), and found a characteristic smectite-rich horizon in the uppermost∼ 5 m of the pelagic clay layer. This horizon should be mechanically weak and will become the future plate boundary fault, as observed in the JFAST cores. The smectite-rich deposits are broadly distributed in the northwestern Pacific Ocean, and may therefore potentially enhance conditions for large shallow slip during earthquakes that occur over a broad area of the Japan Trench plate boundary, which would result in large tsunamis for this region.
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南海海槽浊积楔沉积物物源及扩散规律
DOI：
10.2973/odp.proc.sr.131.105.1993
发表时间：
1993
期刊：
--
影响因子：
--
作者：
M. Underwood;R. Orr;K. Pickering;A. Taira
通讯作者：
A. Taira
影响因子：
3.9
作者：
K. Ujiie;G. Kimura
通讯作者：
K. Ujiie;G. Kimura
影响因子：
3
作者：
Fujii, Yushiro;Satake, Kenji;Kanazawa, Toshihiko
通讯作者：
Kanazawa, Toshihiko
影响因子：
56.9
作者：
Kelin Wang;M. Kinoshita
通讯作者：
M. Kinoshita
影响因子：
56.9
作者：
Ide, Satoshi;Baltay, Annemarie;Beroza, Gregory C.
通讯作者：
Beroza, Gregory C.