Opal‐CT in chert beneath the toe of the Tohoku margin and its influence on the seismic aseismic transition in subduction zones
書誌事項
- タイトル別名
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- Opal-CT in chert beneath the toe of the Tohoku margin and its influence on the seismic aseismic transition in subduction zones
抄録
Thick accumulation of chert is a ubiquitous feature of old oceanic plates at convergent margins. In this study, we investigate chert fragments recovered by the Integrated Ocean Drilling Program expedition 343 at the Japan Trench where the 2011 Tohoku-Oki earthquake (M-w 9.0) occurred. This sample provides a unique opportunity to investigate in situ chert diagenesis at an active subduction margin and its influence on the kinematics of megathrust faulting. Our mineralogical analyses revealed that the chert is characterized by hydrous opal-CT and may therefore be highly deformable via pressure solution creep and readily accommodate shear strain between the converging plates at driving stresses of kilopascal order. As chert diagenesis advances, any further deformation requires stresses of >100MPa, given the increasing transport distances for solutes as represented in cherts on land. The chert diagenesis is thus related to the mechanical transition from a weakly to strongly coupled plate interface at this margin.
収録刊行物
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- Geophysical research letters
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Geophysical research letters 44 (2), 687-693, 2017-01-28
American Geophysical Union
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詳細情報
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- CRID
- 1050845763953054592
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- NII論文ID
- 120006329012
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- ISSN
- 19448007
- 00948276
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- HANDLE
- 2115/66866
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- 本文言語コード
- en
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- 資料種別
- journal article
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- データソース種別
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- IRDB
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