共查询到20条相似文献，搜索用时 156 毫秒
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四川地区强震与发震构造几何结构特征关系的探讨 总被引：1，自引：1，他引：1
本文通过近些年来对四川活动断裂与强震关系的研究，初步总结了四川地区强震与发震构造几何结构特征的关系。作者认为：走滑断层的斜列状结构，断层的交叉，大断裂带的末端，断裂上的枢纽、弯曲、转折部位以及断裂带上的横向隆起、拗主其交替部位都可能是发震构造的结构特征，亦是强震易于发生的部位，这对地震危险区域潜在震源区的划分及其地基预报、地震区划和工程区地震安全性评价具有重要的意义。 相似文献
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浑江断裂带及水系的分形特征和构造活动性研究 总被引：6，自引：0，他引：6
应用分开有几何学方法对浑江断裂带及水系进行了分形特征研究。计算结果表明，浑江断裂带具有较强的活动性，而且次级NNE向断层比NE和NW向断层活动性更强，结合地震活动属于 质地貌，构造应力场等方面的分析。探讨了该断裂带的活动性及区域新构造运动特征。 相似文献
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在灵山地区北西向的六吉－蕉根坪断裂带上，存在着明显的窗棂脊构造地貌。叙述了该构造地貌的特征、形成时间及年变速率，并据此指出，该断裂具有较高的活动性，其地震危险值得注意。该构造地貌的发现为华南地区现今构造应力场和古地震的研究提供了新的信息。 相似文献
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渤海湾盆地构造成因观点剖析 总被引：19，自引：4，他引：15
目前有关渤海湾盆地构造形成机制的解释主要有两种：伸展＋走滑观点和伸展＋拉分观点。这些观点从现有的断层成因模式或应力分析原理出发,强调多种应力方式或多期构造应力场的作用,动力学机制的解释比较复杂。研究表明,盆地边界几何条件（包括裂陷边界几何形态,边界断层的剖面几何形态及性质）和裂陷伸展方向是决定裂陷盆地伸展构造形成特征的关键因素,而砂箱模拟介研究裂陷盆地构造形成过程和机制的重要方法。 相似文献
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华北地区主要构造带的现代运动和应变 总被引：3，自引：0，他引：3
根据网络工程在华北地区1999—2001—2004年的GPS观测资料,计算求解了垂直于断裂构造带走向的线应变率(即断层正应变率)和平行于断裂构造带走向的剪应变率,求解了断裂带的水平错动速率,研究了断裂带的位移和应变状态。断层正应变率表明北东、北北东向断裂带为北段挤压,南段拉张,东西向断裂带和北西向断裂带在华北东部地段为挤压,西部地带为拉张。1999年至2004年的断裂带的正应变率和剪应变率量值都在37×10-9/a以内。断层在水平方向上的活动表明,东西向断裂带和北西向断裂带以左旋运动为主,不同地段兼有拉张或挤压,北东、北北东向断裂带挤压或拉张活动较显著,不同地段兼有右旋或左旋运动。 相似文献
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本文初步研究了阿尔金南、北缘断裂带部分地段的几何学特征,结果显示这两条断裂带的主体部分表现出以左旋走滑为主的活动特征,而其东西两端分别存在有由走滑向逆冲转变的转换段。带内断层分布不连续,存在有多组阶距,许多阶区内发育有拉分盆地和推挤型构造。地震多发生于大尺度阶区及其附近。北缘断裂的西段断层形成较早,东段断层形成相对较晚,断层不连续段之间存在强烈的相互趋近作用,易发生失稳而导致地震发生。断层泥石英颗粒的SEM研究表明,在南缘断裂的苏尔巴斯陶—库什哈段,全新世时期有过强烈活动,距今数百年至1000年内曾发生过一次震级约为7.0—7.5级的地震。作者还总结了几种可能代表古地震事件存在的显微动力学特征。 相似文献
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Comparative microstructures of natural and experimentally produced clay-bearing fault gouges 总被引：2，自引：0，他引：2
Fault rocks formed in phyllosilicate-bearing rocks formed over a wide range of environmental conditions within the Earth's crust are characterised by similar structural and microstructural features. The most striking of these are (a) P foliation, defined by the preferred alignment of phyllosilicates in a plane oblique to the direction of shear and (b) small-scale shear zones either parallel to the shear direction (Y shears) or oblique to the direction of shear but with the opposite sense of obliquity relative to the P foliation (Riedel shears, R1). The minor shear zones have the same sense of displacement as the host shear zone.The occurrence of these and other structures in clay-rich fault gouges from exceptionally well-exposed fault zones in southeastern Spain is described. The pervasive development of these flow structures throughout large volumes of fault gouge permits fault-displacement vectors to be inferred. For the region studied the movement pictures is relatively simple and is superposed on a complex network of variably oriented fault zones.The naturally produced fault-gouge structures are compared with fault gouges produced experimentally by shearing kaolinite-quartz mixtures between intact blocks over a wide range of experimental conditions. Good correspondence between their respective microstructural features was observed.Finally, attention is drawn to the fact that natural clay-bearing fault gouges are the products of deformation accompanied by very low-grade retrogressive metamorphism, and that part of the micro-structure of these rocks may be ascribed to crystallization under stress. Microstructures are described that are from long-duration experimental runs, (5 months at high temperature and in the presence of water) which go some way towards simulating these effects. 相似文献
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介绍了西秦岭北缘断裂带东段和海原断裂带西段的天然断层泥的分形方法和结果，并对断层泥的粒度分布特征与断层运动特性的关系进行了探讨。 相似文献
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程各庄断裂断层泥显微结构特征及其断裂活动性探讨 总被引：1，自引：0，他引：1
程各庄断裂是马坊－夏垫断裂带北段的一条东分支断裂，根据其断层泥的显微结构，石英碎屑ＳＥＭ特征，热释光年龄综合分析，结果表明，该断裂不同区段的最新活动都是以粘滑迷主，但各个区段不同地质时期其活动方式和强度不同。 相似文献
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— On the basis of both experimental and field studies, solution transfer processes are expected to be important in contributing to fault strength recovery (healing) under the hydrothermal conditions prevailing in large parts of the seismogenic zone. However, most experimental work on healing effects in faults has been done using quartzo-feldspathic sliding surfaces or fault gouges, under conditions in which solution transfer processes are very slow. Mechanisms of fluid-assisted fault healing are accordingly rather poorly understood. We have performed slide-hold-slide fault healing experiments on simulated faults containing brine-saturated granular halite as a fault rock analogue. Halite was used because solution transfer processes are known to be rapid in this system under easily accessible conditions. We studied the effects of hold time duration, shear stress during hold, pre-hold sliding velocity and pore-fluid composition on strength evolution. The results show rapid fluid-assisted compaction and stress relaxation during hold periods, and a significant hold time-dependent strengthening upon re-shear. The data reveal that healing resulted from both a packing density increase and a contact area/strength increase during hold periods. The general type of behaviour observed is similar to that observed in quartzo-feldspathic gouges at room temperature, although important differences were observed as well. Notably, the time-dependence of healing deviates from the log-linear trend observed in gouges where solution transfer processes are absent. This means that if pressure solution is an important healing mechanism in natural faults, applying a log-linear trend will underestimate natural fault healing rates. 相似文献
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在不同的压力、温度和孔隙压力下进行了含四种不同断层泥标本的强度试验。碎屑型断层泥对压力很敏感,对温度无反应,对孔隙压力的反应符合有效应力律。粘土类断层泥则对温度和孔隙压力有明显响应。这些力学性质的差别反映了具体变形机制的差别 相似文献
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断层泥是研究活动断裂带运动性质和活动习性的重要介质。以往,对断层泥的研究主要借助偏光显微镜和低真空扫描电镜进行,观察到的现象有限。借助高真空扫描电镜从纳微米尺度对断层泥进行更精细化的研究,其方法是对野外断层泥进行定向原状样品采集,通过室内样品自然风干、微样制作、表面镀金和扫描电镜观察,从纳微米尺度研究a-b组构面和a-c组构面的各种变形现象。此方法可以帮助确定断层的运动性质、断层滑动面的新老关系,并可鉴别粘滑过程与蠕滑过程;同时,还可以对工程场地中发现的黏土滑动面进行鉴别,区分地震断层和非地震断层。 相似文献
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THE GEOLOGICAL AND ROCK MECHANICAL DISTINCTION EVIDENCE BETWEEN STICK-SLIP AND CREEP IN HOST ROCK SEGMENTS OF FAULT 
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下载免费PDF全文 ZHOU Yong-sheng 《地震地质》2019,41(5):1266-1272
Paleo-seismic and fault activity are hard to distinguish in host rock areas compared with soft sedimentary segments of fault. However, fault frictional experiments could obtain the conditions of stable and unstable slide, as well as the microstructures of fault gouge, which offer some identification marks between stick-slip and creep of fault.
We summarized geological and rock mechanical distinction evidence between stick-slip and creep in host rock segments of fault, and analyzed the physical mechanisms which controlled the behavior of stick-slip and creep. The chemical composition of fault gouge is most important to control stick-slip and creep. Gouge composed by weak minerals, such as clay mineral, has velocity weakening behavior, which causes stable slide of fault. Gouge with rock-forming minerals, such as calcite, quartz, feldspar, pyroxene, has stick-slip behavior under condition of focal depth. To the gouge with same chemical composition, the deformation mechanism controls the frictional slip. It is essential condition to stick slip for brittle fracture companied by dilatation, but creep is controlled by compaction and cataclasis as well as ductile shear with foliation and small fold. However, under fluid conditions, pressure solution which healed the fractures and caused strength recovery of fault, is the original reason of unstable slide, and also resulted in locking of fault with high pore pressure in core of fault zone. Contrast with that, rock-forming minerals altered to phyllosilicates in the gouges by fluid flow through degenerative reaction and hydrolysis reaction, which produced low friction fault and transformations to creep. The creep process progressively developed several wide shear zones including of R, Y, T, P shear plane that comprise gouge zones embedded into wide damage zones, which caused small earthquake distributed along wide fault zones with focal mechanism covered by normal fault, strike-slip fault and reverse fault. However, the stick-slip produced mirror-like slide surfaces with very narrow gouges along R shear plane and Y shear plane, which caused small earthquake distributed along narrow fault zones with single kind of focal mechanism. 相似文献