Determining and modeling tectonic movements along the central part of the North Anatolian Fault (Turkey) using geodetic measurements     

Hakan Yavaolu  Ergin Tar&#x;  Okan Tüysüz  Ziyadin ak&#x;r  Semih Ergintav 《Journal of Geodynamics》2011,51(5):339-343

The North Anatolian Fault (NAF), which extends from Karl?ova in Eastern Turkey to the Gulf of Saros in the Northern Aegean Sea, is one of the longest active strike-slip faults in the world with a length of about 1500 km. Within the North Anatolian Shear Zone (NASZ) there are long splays off the main trunk of the NAF veering towards the interior parts of Anatolia. Although the whole shear zone is still seismically active, the major seismicity is concentrated along the main branch of the NAF. Splays of the NAF dissect the shear zone into different continental blocks. The largest splay of the NAF was selected to analyze the distribution of movements between the faults delimiting these blocks. Four years of GPS measurements and modeling results indicate that the differential motion between the Anatolian collage and the Eurasian plate along the central part of the NAF is partitioned between fault splays and varies between 18.7 ± 1.6 and 21.5 ± 2.1 mm/yr with the main branch taking ∼90% of the motion.  相似文献   

徐州废黄河断裂带的空间展布与活动性研究   总被引：1，自引：0，他引：1       下载免费PDF全文

陈丁  张景发  朱鲁  姜文亮  路晓翠  刘建达  李丽梅  张鹏 《地震地质》2011,33(1):67-78

文中利用遥感影像分析了徐州废黄河断裂带的空间展布及与邵楼断裂的交切关系,利用重磁资料研究了废黄河断裂带的深部几何结构及与郯庐断裂带西边界的交切关系。二阶布格重力异常小波变换细节图反映出徐州废黄河断裂带的深度为7～8km,而三阶和四阶重力异常细节图反映的深度分别为9～11km和15～18km。研究结果表明,废黄河断裂带向SE延伸至九顶附近,向下的切割深度约为 8～9km。NW向的废黄河断裂带截切邵楼断裂致使邵楼断裂构造线自东北向西南由N60°E转至N45°E。废黄河断裂带与郯庐断裂带不相交。废黄河断裂带属于前第四纪断裂,活动性较弱。  相似文献   

基于高分辨率DEM的裂点序列提取和古地震序列的识别——以霍山山前断裂为实验区   总被引：6，自引：4，他引：2       下载免费PDF全文

毕丽思  何宏林  徐岳仁  魏占玉  石峰 《地震地质》2011,(4):963-977

以霍山山前断裂为实验区,基于高分辨率IRS-P5 DEM数据提取了横穿断裂的冲沟,在23条冲沟纵剖面上识别出断裂活动诱发裂点.在其中5条冲沟上识别出1级裂点,裂点几乎位于断裂上;在2条冲沟上识别出2级裂点,最新裂点也位于断裂上.这些位于断裂上的裂点,高度达4～9m,推测它们形成之后并未向上游明显迁移,并可能接受了多次事...  相似文献   

Disappearing ink: How pseudotachylytes are lost from the rock record     

《Journal of Structural Geology》2013

Melt-origin pseudotachylytes are the most widely accepted feature recording earthquake slip in the fault rock record. However, reports of pseudotachylytes are rare compared to the frequency and distribution of earthquakes in active faults, suggesting melting occurs only under exceptional circumstances and therefore that pseudotachylytes are rarely formed. In this paper, we document the processes whereby pseudotachylytes are overprinted, destroyed and otherwise removed from the rock record. We present examples of recrystallized, altered, and cataclastically and crystal plastically deformed pseudotachylytes from a variety of ancient faults. Based on these observations, we identify characteristics of pseudotachylytes that are resistant to change over geologic time and develop criteria to allow recognition of relict pseudotachylytes. Our results imply that pseudotachylytes are vastly under-reported due to their vulnerability to destruction and the resulting difficulty in identification. As a consequence, the significance of frictional melting is underestimated. The criteria we propose to distinguish relict pseudotachylytes can help to reconcile the observed frequency of earthquakes with the difficulty of demonstrating ancient seismic slip in the rock record.  相似文献   

红河断裂带莺歌海段地质构造特征   总被引：3，自引：0，他引：3  

孙桂华  彭学超  黄永健 《地质学报》2013,87(2):154-166

红河入海后的地质构造特征研究是当前红河断裂带研究的薄弱环节.结合莺歌海地区重力和地震资料解释与前人研究成果,系统总结了红河断裂带莺歌海盆地内的几何学、运动学特征,并根据莺歌海盆地沉积中心迁移规律获得了红河断裂带的年代学数据.研究认为:红河断裂带在入海口附近分叉,其中Tien Lang断层折向NE,呈马尾状展布;在莺歌海盆地内红河断裂带分支为A(Ⅰ号断层)、B、C和D(莺西断层)4条断层,其中A断层是最主要的一条分支断层.莺歌海盆地内的分支断层均呈近NW-SE走向,延伸420～500km,其地震解释剖面上发育的典型花状构造和马尾状Tien Lang断层共同指示该断层具有走滑运动性质;红河断裂带对莺歌海盆地的沉积具有明显的控制作用,盆地沉积中心变化规律揭示红河断裂带在30～15.5Ma期间具有左行走滑运动性质,15.5～5.5Ma期间为左行向右行转换阶段,发生了强烈的构造反转作用,5.5Ma以来具有右行走滑运动特征.  相似文献   

Suckling Dome and the Australian–Woodlark plate boundary in eastern Papua: the geology of the Keveri and Ada'u Valleys     

I. D. Lindley 《Australian Journal of Earth Sciences》2013,60(8):1125-1147

The Owen Stanley Fault Zone (OSFZ) is the low-angle thrust boundary between the Australian and Woodlark plates. The eastern extension of the OSFZ links with the Woodlark Basin spreading centre. Recent tectonic models of eastern Papua depict the OSFZ boundary passing through the Mt Suckling district, with the Keveri Fault a key component. Gravity data clearly show that the OSFZ and the Papuan Ultramafic Belt (PUB) pass north of Mt Suckling. Tectonised mafic and ultramafic rocks of the Mt Suckling district, previously referred to the PUB, are reassigned to the Awariobo Range Complex (new name). Extensive pillow basalts previously referred to the middle Eocene part of the Kutu Volcanics at the top of the PUB sequence are, in the map area, reassigned on lithological and biostratigraphic grounds to the late Oligocene–middle Miocene Wavera Volcanics. The detailed work reported here indicates that the Keveri Fault is unrelated to the OSFZ with no evidence for thrusting along the structure. The area's tectonic history has been dominated by large vertical displacements along the Keveri Fault. The commencement of late Miocene buoyant uplift of the Suckling Dome (new name), related to granite intrusion into thick crust of the eastern Papua region, marks the inception of the Keveri Fault and coincides with the initiation of Woodlark rifting. The fault facilitated much of the rapid vertical movement of the dome, with an estimated 8000 m of uplift (2.5 m/10³ a) since the late Miocene. Movement on the Keveri Fault is notably different from structures flanking other metamorphic core complexes in eastern Papua. There is no field evidence for the development of a low-angle, south-dipping detachment fault along the southern margin of the Suckling Dome. The Suckling Dome is the westernmost of the eastern Papua domes, localised within a broad extensional zone that continues to propagate westward along the OSFZ plate boundary.  相似文献   

Structural inversion and its controls : examples from the Alpine foreland and the French Alps     

Ralph Gillcrist  Mike Coward  Jean-Louis Mugnier 《Geodinamica Acta》2013,26(1):5-34

Abstract

Positive structural inversion involves the uplift of rocks on the hanging-walls of faults, by dip slip or oblique slip movements. Controlling factors include the strike and dip of the earlier normal faults, the type of normal faults — whether they were listric or rotated blocks, the time lapsed since extension and the amount of contraction relative to extension. Steeply dipping faults are difficult to invert by dip slip movements; they form buttresses to displacement on both cover detachments and on deeper level but gently inclined basement faults. The decrease in displacement on the hanging-walls of such steep buttresses leads to the generation of layer parallel shortening, gentle to tight folds — depending on the amount of contractional displacement, back-folds and back-thrust systems, and short-cut thrust geometries — where the contractional fault slices across the footwall of the earlier normal fault to enclose a “floating horse”. However, early steeply dipping normal faults readily form oblique to strike slip inversion structures and often tramline the subsequent shortening into particular directions.

Examples are given from the strongly inverted structures of the western Alps and the weakly inverted structures of the Alpine foreland. Extensional faulting developed during the Triassic to Jurassic, during the initial opening of the central Atlantic, while the main phases of inversion date from the end Cretaceous when spreading began in the north Atlantic and there was a change of relative motion between Europe and Africa. During the mid-Tertiary well over 100 km of Alpine shortening took place; Alpine thrusts, often detached along, or close to, the basement-cover interface, stacking the late Jurassic to Cretaceous sediments of the post-extensional subsidence phase. These high level detachments were joined and breached by lower level faults in the basement which, in the external zones of the western Alps, generally reactivated and rotated the earlier east dipping half-graben bounding faults. The external massifs are essentially uplifted half-graben blocks. There was more reactivation and stacking of basement sheets in the eastern part of this external zone, where the faults had been rotated into more gentle dips above a shallower extensional detachment than on the steeper faults to the west.

There is no direct relationship between the weaker inversion of the Alpine foreland and the major orogenic contraction of the western Alps; the inversion structures of southern Britain and the Channel were separated from the Alps by a zone of rifting from late Eocene to Miocene which affected the Rhone, Bresse and Rhine regions. Though they relate to the same plate movements which formed the Alps, the weaker inversion structures must have been generated by within plate stresses, or from those emanating from the Atlantic rather than the Tethyan margin.  相似文献   

Research on Heterogeneity and Dynamic Genesis of the Present Tectonic Stress Field in Tianshan Mountain Zone     

ZHANG Hongyan  XIE Furen  CUI Xiaofeng 《《地质学报》英文版》2013,87(Z1):429-429

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Holocene slip rate of northern Gyaring Co Fault along Karakorum-Jiali Fault Zone (KJFZ), in central Tibet     

WANG Duo  YIN Gongming  JIANG Yafeng  HAN Fei  CHUNG Lingho 《《地质学报》英文版》2013,87(Z1):391-392

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复杂断层构造电磁波衰减系数层析成像模拟研究     

刘鑫明  刘树才  易洪春  杨光  刘英 《地球科学进展》2013,28(3):391-397

传统矿井电磁波透视层析成像技术只考虑电磁波的传播距离而忽视传播的方向性,造成探测复杂构造时的层析成像分辨率较低。依据电磁波在煤岩介质中的传播规律推导出了与入射角有关的新振幅衰减常数。引用新振幅衰减常数并基于代数重建算法建立了层析成像数学模型,编制了程序软件。利用新振幅衰减常数层析成像算法分别对平行和交叉断层进行数值模拟。通过与传统衰减常数层析成像的效果进行对比,结果表明:改进后的新振幅衰减常数层析成像效果更好,对断层的位置、走向、延展长度等情况反映清晰准确;在介质背景衰减场不易确定的情况下,绝对衰减层析成像方式优于相对衰减层析成像方式;平行关系的断层构造分辨率要高于交叉关系的断层构造。通过在某采煤工作面的电磁波层析成像中成功圈定了一组隐伏的平行断层构造实例,说明采用新衰减常数的层析成像技术效果提高明显。  相似文献