The role of dehydration reaction in seismogenic processes at subduction plate boundaries

脱水反应在俯冲板块边界地震过程中的作用

• 批准号: 19340147
• 负责人: SHIMIZU Ichiko
• 金额: $ 12.4万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2007
• 资助国家: 日本
• 起止时间: 2007 至 2009
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-19340147/
• 关键词: レオロジー; 地殼マントル物質; 沈み込み帯; 中深発地震; 岩石レオロジー; 高温高圧変形実験; 含水量; 差応力; 脆性-延性転移; 固体圧試験機; 蛇紋岩; 脱水反応; 沈み込みスラブ; 地震; アンチゴライト; 応力-歪曲線; 固体圧式変形試験機; 応力; 脆性一延性; 地震発生構; 流体; 後方電子散乱増

A popular hypothesis for the occurrence of double seismic zones, observed at the intermediate depth of about 50-200km, is dehydration embrittlement of the serpentinized slab mantle. The weakening of serpentinite was attributed to excess pore fluid pressure caused by dehydration reaction of serpentine. However, the confining pressure of these experiments using gas-medium apparatus was limited up to 500MPa (corresponding to 15km depth). It is questionable if the same mechanism could be effective in subducting slabs at higher pressures. We conducted constant strain-rate experiments of serpentinite using a solid-medium deformation apparatus and found that the yield strength of serpentinites drastically decreased when dehydration reaction proceeded. This phenomena, named "dehydration weakening", would be a key to understand seismogenic processes in the serpentinized mantle slabs.

对于在50- 200 km的中间深度观测到的双地震带的存在，一个流行的假说是蛇纹化板幔的脱水脆化。蛇纹岩的弱化是由于蛇纹岩脱水反应产生的超孔隙流体压力所致。然而，使用气体介质装置的这些实验的围压被限制到500 MPa（对应于15 km深度）。同样的机制是否能在高压下有效地俯冲板，这是值得怀疑的。利用固体介质变形仪对蛇纹岩进行了恒应变速率实验，发现蛇纹岩的屈服强度随着脱水反应的进行而急剧下降。这一现象被称为“脱水弱化”，它将是理解蛇纹化地幔板孕震过程的关键。

项目成果

蛇紋岩の脆性-延性転移

蛇纹岩的脆性转变

• 发表时间: 2009
• 作者: Suzuki;H.;清水以知子
• 通讯作者: 清水以知子

かんらん岩の構造敏感性と弾性的異方性

橄榄岩的结构敏感性和弹性各向异性

• 发表时间: 2008
• 期刊: 地学雑誌 117
• 作者: Dyrland;M.;Masafumi Imai;道林 克禎
• 通讯作者: 道林 克禎

B-type olivine fabrics developed in the fore-arc side of the mantle wedge along a subducting slab

• DOI: 10.1016/j.epsl.2008.06.014
• 发表时间: 2008-08
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: M. Tasaka;K. Michibayashi;D. Mainprice

Grain growth systematics for forsterite ± enstatite aggregates: Effect of lithology on grain size in the upper mantle

• DOI: 10.1016/j.epsl.2009.12.026
• 发表时间: 2010-03-01
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Hiraga, Takehiko;Tachibana, Chihiro;Sano, Satoru
• 通讯作者: Sano, Satoru

Theories and applicability of grain slze piezometers: The role of dynamic recrystallization mechanisms.

晶粒尺寸压力计的理论和适用性：动态再结晶机制的作用。

• 发表时间: 2008
• 期刊: Journal of Structural Geology 30
• 作者: Shimiz;I.
• 通讯作者: I.