Frictional properties of JFAST core samples and implications for slow earthquakes at the Tohoku subduction zone
Frictional properties of JFAST core samples and implications for slow earthquakes at the Tohoku subduction zone
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JFAST岩心样本的摩擦特性及其对东北俯冲带慢地震的影响
DOI：
10.1002/2017gl073460
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发表时间：
2017
影响因子：
5.2
通讯作者：
Christopher J. Spiers
中科院分区：
文献类型：
--
作者：
Michiyo Sawai;Andre R. Niemeijer;Takehiro Hirose;Christopher J. Spiers
慢地震发生在东北俯冲带的浅部（深度<20公里）。为了了解板块边界断层的摩擦特性如何影响这些慢地震的产生，我们使用在综合大洋钻探计划远征343（日本海沟快速钻探项目（JFAST））期间从板块边界滑脱和下盘取回的钻孔样品进行摩擦实验。板块边界断层材料在50 ° C至150°C之间表现出从速度强化到速度弱化的转变，在速率和状态摩擦定律的框架下，这是产生慢地震的必要条件，而下盘样品主要表现出速度强化行为，除了在<50°C的温度下。日本海沟慢地震的下倾温度极限也在100到150°C之间。我们的研究结果表明，板块边界断层的摩擦性质可能在控制观测到的慢地震的位置起着关键作用。
Slow earthquakes occur in the shallow (<20 km deep) part of the Tohoku subduction zone. To understand how frictional properties of the plate boundary fault affect the generation of these slow earthquakes, we conducted friction experiments using borehole samples retrieved from the plate boundary décollement and footwall during Integrated Ocean Drilling Program Expedition 343 (Japan Trench Fast Drilling Project (JFAST)). The plate boundary fault material exhibits a transition from velocity‐strengthening to velocity‐weakening behavior at temperatures between 50 and 150°C, which, in the framework of rate‐and‐state friction laws, is a necessary condition for the generation of slow earthquakes, whereas the footwall sample mainly shows velocity‐strengthening behavior except at temperatures of <50°C. The downdip temperature limit of slow earthquakes in the Japan Trench also lies between 100 and 150°C. Our results suggest that the frictional properties of the plate boundary fault may play a key role in controlling the locations of observed slow earthquakes.