Distribution of fault rocks in the fracture zone of the Nojima Fault at a depth of 1140 m: Observations from the Hirabayashi NIED drill core
Distribution of fault rocks in the fracture zone of the Nojima Fault at a depth of 1140 m: Observations from the Hirabayashi NIED drill core
复制标题
1140 m 深度野岛断层断裂带断层岩石分布：平林 NIED 钻芯观测
DOI：
10.1111/j.1440-1738.2001.00339.x
复制
发表时间：
2001
期刊：
影响因子：
1.5
通讯作者：
A. Yamazaki
中科院分区：
文献类型：
--
作者：
Kenta Kobayashi;S. Hirano;T. Arai;R. Ikeda;K. Omura;H. Sano;T. Sawaguchi;Hidemi Tanaka;Tomoaki Tomita;N. Tomida;Tatsuo Matsuda;A. Yamazaki
根据平林国立地球科学与灾害预防研究所（NIED）钻孔岩芯的细观（肉眼）和微观（光学显微镜和扫描电子显微镜）观察，描述了野岛断层1140 m深断裂带的变形和蚀变特征。三种类型的断层岩;在断裂带中部出现断层角砾岩、断层泥和碎裂岩，在断裂带中部以外（破坏带）出现弱变形蚀变花岗闪长岩和蚀变花岗闪长岩两种类型。破碎带中偶见碎裂岩。六个明显的薄层状断层泥带，倾向于东南方向，清晰地出现在断裂带的中心部分。在最新的断层泥表面上观察到向东北方向倾斜的滑线。根据XZ薄片的观测结果，这些滑塌线和最新断层泥与1995年兵库县南部地震（科比地震）具有相同的运动学特征，即右旋-反向滑动。断层泥冷冻干燥后的扫描电镜观察表明，断层泥中局部存在大量的孔隙空间，这可能是流体运移的通道，也可能是孔隙流体压力不均匀性或应变局部化的存在。
Abstract Characteristics of deformation and alteration of the 1140 m deep fracture zone of the Nojima Fault are described based on mesoscopic (to the naked eye) and microscopic (by both optical and scanning electron microscopes) observations of the Hirabayashi National Research Institute for Earth Science and Disaster Prevention (NIED) drill core. Three types of fault rocks; that is, fault breccia, fault gouge and cataclasite, appear in the central part of the fault zone and two types of weakly deformed and/or altered rocks; that is, weakly deformed and altered granodiorite and altered granodiorite, are located in the outside of the central part of the fault zone (damaged zone). Cataclasite appears occasionally in the damaged zone. Six distinct, thin foliated fault gouge zones, which dip to the south‐east, appear clearly in the very central part of the fracture zone. Slickenlines plunging to the north‐east are observed on the surface of the newest gouge. Based on the observations of XZ thin sections, these slickenlines and the newest gouge have the same kinematics as the 1995 Hyogo‐ken Nanbu earthquake (Kobe earthquake), which was dextral‐reverse slip. Scanning electron microscopy observations of the freeze‐dried fault gouge show that a large amount of void space is maintained locally, which might play an important role as a path for fluid migration and the existence of either heterogeneity of pore fluid pressure or strain localization.