| 安宁河断层地震成核条件研究——来自天然花岗岩断层泥摩擦实验的启示 |
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| 引用本文： | 雷蕙如,周永胜,姚文明,马玺,何昌荣,党嘉祥,苗社强,戴文浩.安宁河断层地震成核条件研究——来自天然花岗岩断层泥摩擦实验的启示[J].地球物理学报,2022,65(3):978-991. |
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| 作者姓名： | 雷蕙如 周永胜 姚文明 马玺 何昌荣 党嘉祥 苗社强 戴文浩 |
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| 作者单位： | 中国地震局地质研究所地震动力学国家重点实验室,北京 100029 |
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| 基金项目： | 国家重点研发项目(2018YFC1503400)资助。 |
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| 摘 要： | 安宁河断层历史上发生过多次强震,现存的地震空区反映了其断层中部近30年来的断层闭锁和应变积累情况,是潜在的大地震危险区.本研究采用断层带内的新鲜花岗岩断层泥样品,在水热条件下开展了摩擦滑动实验,以研究安宁河断层摩擦特性和地震成核条件.实验有效正应力200MPa,孔隙水压30 MPa,温度25～600℃,剪切滑移速率在1...
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| 关 键 词： | 花岗岩断层泥 安宁河断层 摩擦强度 速度依赖性 地震成核 |
Earthquake nucleation conditions of Anninghe Fault:constrains from frictional experiments on natural granite gouge |
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| LEI HuiRu,ZHOU YongSheng,YAO WenMing,MA Xi,HE ChangRong,DANG JiaXiang,MIAO SheQiang,DAI WenHao.Earthquake nucleation conditions of Anninghe Fault:constrains from frictional experiments on natural granite gouge[J].Chinese Journal of Geophysics,2022,65(3):978-991. |
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| Authors: | LEI HuiRu ZHOU YongSheng YAO WenMing MA Xi HE ChangRong DANG JiaXiang MIAO SheQiang DAI WenHao |
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| Institution: | (State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China) |
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| Abstract: | The“Anninghe seismic gap”reflects fault-locking and associated strain-accumulation along with the central part of the Anninghe Fault over the last 30 years,and is considered a high possibility location for future earthquakes.In this study,we performed frictional experiments of natural granite gouges from the Anninghe Fault core under hydrothermal conditions.Velocity-stepping experiments were performed at effective normal stress of 200 MPa,pore fluid pressure of 30 MPa,temperature from 25 to 600℃,and shear velocities between 0.04μm·s-1 and 1μm·s-1.Results show that the friction coefficient(about 0.663~0.704)increases at 100~400℃followed by a decrease at 400~600℃.The slip stability response is characterized by velocity strengthening at temperatures of 25~100℃and velocity weakening at temperature of 200~600℃.The upper temperature limit for unstable sliding of granite gouges is 600℃,which is much higher than the 350~400℃upper limit of unstable sliding temperature given by previous data.The results also show that the stability of granite fault is related to the loading rate at the same temperature,which the velocity-weakening region is more likely to occur at the lower rate or slow velocity(0.04μm·s-1).Based on the experimental results and combined with the geothermal gradient in Sichuan-Yunnan Block,it is inferred that the depth of seismic nucleation is 10~30 km in the middle and northern section of the Anninghe Fault,which implies that the earthquake gap should be a kind of interseismic locking along the Anninghe Fault. |
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| Keywords: | Granite gouge Anninghe Fault Friction strength Velocity dependence Earthquake nucleation |
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