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1.
内蒙古狼山地区断裂构造十分复杂,主要发育有南北、东西、北东和北西走向的断裂构造.从南北向断裂的几何形态、运动性质、构造应力场特征入手进行研究,结合野外实地调查与测量,运用极射赤平投影方法,求出构造应力场的主应力轴方位,进而对本区的构造演化进行了探讨.初步认为,研究区发育的近南北向断裂至少受到过两期构造应力场的作用,第一期是在晚二叠世,由于华北克拉通向北、西伯利亚板块向南活动而形成碰撞拼贴运动所产生的近南北向近水平挤压构造应力场,此时构造应力场的主应力轴σ1为北偏东10°左右,向北倾伏,倾伏角为15°~20°.在这一期构造应力场的作用下,狼山地区发育了一套破裂系统,它们分别表现为近东西走向的挤压构造带和逆断层、近北东走向的以左行为主的走滑断层、近北西走向的以右行为主的走滑断层以及近南北走向的张性断层.这些早期的断裂系统也制约着该区域后来的构造活动,第二期构造应力场是侏罗纪以来古太平洋板块向亚洲大陆俯冲而产生的.此构造应力场的主应力轴σ1为北西-南东向,倾伏向为150°左右,倾伏角为10°~20°.第二期构造应力场的作用,使早期南北向断裂由原来的张性破裂面转为左行走滑,早期东西向断裂转为右行走滑,早期北东向左行滑动面转为压性面和褶皱轴方向,而早期的北西向破裂面则转为张性破裂性质. 相似文献
2.
基于区域地震台网的数字化波形资料,使用ISOLA方法对2019年5月18日吉林松原M5.1地震进行矩张量反演,研究地震的震源机制,并且收集了地震序列中ML2.5以上地震的震源机制解,采用FMSI（focal mechanism stress inversion）方法反演震中区构造应力场。结果显示：松原M5.1地震的矩震级为4.9,矩心深度为6 km,双力偶分量为91.5%,主压应力P轴方位角、倾角分别为76°和3°,主张应力T轴方位角、倾角分别为166°和16°,震源机制解显示典型的构造地震特征;震中区构造应力场理论应力轴σ1方位角、倾伏角分别为88.0°和0.9°,σ2方位角、倾伏角分别为178.2°和9.6°,σ3方位角、倾伏角分别为352.5°和80.4°,这一结果与区域构造应力场一致。推断认为区域构造应力场触发了2019年松原M5.1地震活动,地震震源机制解的北西向节面与震中区附近的第二松花江断裂现今活动性质完全一致,认为第二松花断裂可能是松原M5.1地震的发震断层。 相似文献
3.
青藏高原中部的东西向扩张构造运动 总被引：3，自引：0，他引：3
系统分析了1933~2003年间青藏高原及其周缘发生的745个中、强地震的震源机制解,研究了高原地壳构造运动及其动力学特征。结果表明,大量正断层型地震集中发生在青藏高原中部海拔4000m以上的地区,其中许多地震是纯正断层型地震。震源机制结果显示,该区正断层型地震的断层走向多为南北方向,断层位错矢量的水平分量均位于近东西方向,这表明青藏高原高海拔地区存在着近东西方向的扩张构造运动。地震震源应力场的研究结果表明,在高原中部高海拔地区,E-W向或WNW-ESE向的水平扩张作用控制着该区的地壳应力场。青藏高原高海拔地区近东西方向的扩张构造运动是该区引张应力场的作用结果,其动力学原因可能与持续隆升的高原自重增大引起的重力崩塌及其周边区域构造应力状况有关。而青藏高原周缘地区,除了东部边缘外,南部的喜马拉雅山前沿以及青藏高原的北部、西部边缘所发生的绝大部分地震都是逆断层型或走滑逆断层型地震。在青藏高原周缘地区,北东或者北北东方向水平挤压的构造应力场为优势应力场。在中国西部的大范围内,主压应力P轴水平分量位于NE-SW方向,形成了一个广域的NE-SW方向的挤压应力场。青藏高原及其周缘应力场特征表明,印度板块的北上运动以及它与欧亚板块之间的碰撞所形成的挤压应力场是高原强烈隆起的直接原因。在青藏高原中南部形成了近东西向引张应力场为主的区域,并以东西向扩张构造运动部分释放其应力积累。研究高原高海拔地区的引张应力场和近东西向扩张构造运动的特征,对于认识青藏高原强烈隆起的地球动力学过程与机制,有着重要的理论意义。 相似文献
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本文系统解析并分析了1931年8月-2005年10月期间青藏高原及其周围发生的905个震级M4．5-8．5地震的震源机制结果,研究了青藏高原岩石圈的区域应力场与构造运动特征。结果表明,来自印度板块的北北东或北东方向的水平挤压应力控制了青藏高原及其周缘地区的岩石圈应力场。从喜马拉雅到贝加尔湖以南包括中国西部的广大范围内,主压应力P轴的水平分量位于近NE-SW方向,形成了一个广域的NE-SW方向的挤压应力场。特别是青藏高原周缘地区,除其东部边缘外,南部的喜马拉雅山前沿以及青藏高原的北部、西部边缘地区所发生的绝大部分地震都属于逆断层型或走滑逆断层型地震,表现出周缘地区的水平挤压应力更为强势。应力场特征充分表明, 印度板块的北上运动,以及它与欧亚板块之间的碰撞,所形成的挤压应力场是青藏高原强烈隆起的直接原因。在青藏高原周缘地区受到强烈挤压应力场控制的同时,有大量正断层型地震集中发生在青藏高原中部海拔4000m以上的地区,其中许多地震是纯正断层型地震。震源机制结果显示,近E-W向或WNW-ESE向的水平扩张应力控制着该区的岩石圈应力场;正断层型地震的断层走向多为南北方向,断层位错矢量的水平分量大体位于近东西方向。这表明青藏高原中部高海拔地区存在着近东西方向的扩张构造运动,且扩张构造运动是该区引张应力场的作用结果。其动力学原因可能与持续隆升的高原自重增大引起的重力崩塌及其周边区域构造应力状况有关。研究青藏高原存在挤压应力场与引张应力场及其构造运动的区域特征,对于认识青藏高原形成、发展的地球动力学机制,有着极其重要的意义。 相似文献
5.
笔者系统分析了1918—2005年间中国大陆及其周缘发生的3130个中、强地震的震源机制解,根据其特征进行了岩石圈应力场构造分区,首次得到区域应力场的压应力轴和张应力轴空间分布的统计数字结果。在此基础上研究了应力场的区域特征、探讨了其动力学来源以及构造运动特征。总体结果表明,中国大陆及其周缘岩石圈应力场和构造运动可以归结为印度洋板块、太平洋板块、菲律宾海板块与欧亚板块之间相对运动,以及大陆板内区域块体之间的相互作用的结果。印度洋板块向欧亚板块的碰撞挤压运动所产生的强烈的挤压应力,控制了喜马拉雅、青藏高原、中国西部乃至延伸到天山及其以北的广大地区。在青藏高原周缘地区和中国西部的大范围内,压应力P轴水平分量方位位于20～40°,形成了近NE方向的挤压应力场。大量逆断层型强震集中发生在青藏高原的南、北和西部周缘地区,以及天山等地区。而多数正断层型地震集中发生在青藏高原中部高海拔的地区,断层位错的水平分量位于近东西方向。表明青藏高原周缘区域发生南北向强烈挤压短缩的同时,中部高海拔地区存在着明显的近东西向的扩张运动。中国东部的华北地区受到太平洋板块向欧亚板块俯冲挤压的同时,又受到从贝加尔湖经过大华北直到琉球海沟的广阔地域里存在着的统一的、方位为170°的引张应力场的控制。华北地区大地震的震源机制解均反映出该区地震的发生大体为NEE向挤压应力和NNW向张应力的共同作用结果。台湾纵谷断层是菲律宾海板块与欧亚板块之间碰撞挤压边界。来自北西向运动的菲律宾海板块构造应力控制了从台湾纵谷、华南块体,直到中国南北地震带南段东部地域的应力场。地震的震源机制结果还表明,将中国大陆分成东、西两部分的中国南北地震带是印度洋板块、菲律宾海板块与太平洋板块在中国大陆内部影响控制范围的分界线。 相似文献
6.
成矿构造应力场研究是控矿构造研究、认识矿体空间展布形态、位置、预测及布置探矿设计的基础。依据弹性力学和莫尔库仑剪切破裂理论,推导出形成共轭及在剪切构造带内形成羽列、雁列等构造应力场的产状和形成羽列、雁列主应力大小的数学解析表达式,进而应用计算机对新城金矿床主矿体进行了测算。结果显示：该矿主容矿构造是在NNW向缓倾拉张主应力、NE向陡倾主压应力、焦家构造带平面呈右行扭动下形成的。NWW向中间主应力控制新城Ⅰ号主矿体在NW向倾斜平面上延深的长轴方向。该轴在水平面上投影的倾伏向为281°,与水平面的夹角倾伏角为26°,在N40°E纵投影面上向SW侧伏,侧伏角为45°,富矿柱产状亦与中间主应力轴产状一致。在已获取容矿构造产状基础上,据相关岩石力学性质测试成果,分析并建立了主容矿羽列与控制剪切构造带两者的力学关系和剪切破裂方程式。联立解出成矿应力场的最大和最小主应力的量值,再由陡倾主应力大小估算出该矿头部的成矿深度在2 750 m左右。 相似文献
7.
根据野外地质调查结果并结合区域地质资料, 对2019年长宁MS6.0地震震区的地质背景和新构造运动特征进行分析后, 讨论了此次地震的发震构造并给出该地区孕震模型。基于区域地质与地震资料, 结合地表调查结果发现, 该区的新构造运动具有间歇性整体弱隆升、断裂晚第四纪活动不明显以及地震活动相对微弱等特征。此次强震的仪器震中位于长宁双河大背斜的西段, 该背斜经历了古老的NE向挤压应力场和顺时针旋转应力场的双重叠加构造作用。在大背斜的核部和翼部普遍发育了两组NW向节理和一组NE向节理, 并显示出区域性分布特征, 构成了具一定规模的构造破碎带(软弱带)。地震记录显示, 此次强震的地震序列呈现出明显的NW向线性条带, 震源机制解主要指示了NEE—NE向水平挤压应力作用的结果。结合地表构造特征可进一步推断, 长宁地震的震源破裂型式是以沿NW向破裂面发生以逆冲为主兼具左旋走滑分量的破裂过程为特征。综合分析认为, 2019年长宁MS6.0地震可能是双河背斜中的赋存超压环境叠加NE向古构造应力场和旋转应力场作用, 导致区域性NW向纵向节理发生构造强化、贯通, 并进一步破裂的结果。 相似文献
8.
成矿构造应力场研究是控矿构造研究、认识矿体空间展布形态、位置、预测及布置探矿设计的基础。依据弹性力学和莫尔库仑剪切破裂理论,推导出形成共轭及在剪切构造带内形成羽列、雁列等构造应力场的产状和形成羽列、雁列主应力大小的数学解析表达式,进而应用计算机对新城金矿床主矿体进行了测算。结果显示：该矿主容矿构造是在NNW向缓倾拉张主应力、NE向陡倾主压应力、焦家构造带平面呈右行扭动下形成的。NWW向中间主应力控制新城Ⅰ号主矿体在NW向倾斜平面上延深的长轴方向。该轴在水平面上投影的倾伏向为281°,与水平面的夹角倾伏角为26°,在N40°E纵投影面上向SW侧伏,侧伏角为45°,富矿柱产状亦与中间主应力轴产状一致。在已获取容矿构造产状基础上,据相关岩石力学性质测试成果,分析并建立了主容矿羽列与控制剪切构造带两者的力学关系和剪切破裂方程式。联立解出成矿应力场的最大和最小主应力的量值,再由陡倾主应力大小估算出该矿头部的成矿深度在2 750 m左右。 相似文献
9.
中国东部海域及其邻区现代构造应力场研究 总被引：2，自引：0，他引：2
中国东部海域是指渤海、黄海和东海地区。前人利用震源机制解、井壁崩落和水压致裂等资料,分别对有关海区的现代构造应力场作过不同程度的研究。文中根据前人的工作并结合海陆地区新构造运动及其动力条件分析,对东部海域及邻区的现代构造应力场进行较深入的研究。该区现代构造应力场以水平至近于水平挤压作用为主要特征,压应力方向从北到南由NE逐渐转为NEE、EW、SEE至SE向,总体呈向东发散的扇形分布。构造应力作用强度具有非一致性,北强南弱。海域具有与大陆统一的现代构造应力场,相应可划为东北、华北和华南3个应力区。中国东部大陆和海域在青藏高原东部被印度板块挤出的构造块体往NE-SE方向滑动推挤及东边太平洋和菲律宾海板块向NWW俯冲推挡的共同作用下,形成现代构造应力场,且青藏高原东部被挤出块体东向滑动的推挤是现代构造应力场产生的主要动力。 相似文献
10.
一、引言第四纪以来由于印度板块持续向北推挤和蒙古—阿拉善地块相对向南的阻挡,导致青藏高原北东地区向东侧向挤出,致使该地区最大主应力方向由北东转为北东东,应力结构也以早期从挤压逆冲为主转为以走滑为主,本文通过在相应方式应力作用下的构造活动所产生的地质现象来论证该地区构造应力场转变的地质时期。 相似文献
11.
Kusumawardani Rini Chang Muhsiung Upomo Togani Cahyadi Huang Ren-Chung Fansuri Muhammad Hamzah Prayitno Galih Ady 《Landslides》2021,18(9):3163-3182
Landslides - The Palu-Donggala earthquake struck Palu city of Sulawesi island, Indonesia, on 28 September 2018. A large-scale liquefaction phenomena occurred in some areas which caused massive... 相似文献
12.
Indonesia is one country in the world featuring a complex tectonic structure. This condition makes earthquakes often occur in many areas of this country and as an earthquake rages beneath the sea, it will potentially trigger tsunami. One of the areas in Indonesia with a high seismic activity is Sulawesi region particularly in the Sulawesi Sea subduction zone, making it important to carry out a study on the potential tsunami at this location. The purpose of this study was to analyze the existing huge potential energy in Sulawesi Sea subduction zone and to identify tsunami modeling likely to occur based on the potential energy of the region. The approach used in assessing the tsunami disaster was the calculation of the potential energy of an earthquake and tsunami modeling based on the potential energy. The method used in this research was the least squares method for the calculation of potential energy, and near-field tsunami modeling with the assistance of TUNAMI-N2 COD. The research finding has shown that the Sulawesi Sea subduction zone has potential energy of 1.35469?×?1023 erg, equivalent to an earthquake with a magnitude of 7.6 Mw. The tsunami modeling made shown the average wave propagation reaching ashore within 12.3 min with a height varying between 0.1 and >?3 m. The tsunami modeling also indicated that there are seven sub-districts in Buol District, Central Sulawesi, which is affected by a significant tsunami. 相似文献
13.
John A. Katili 《Tectonophysics》1978,45(4):289-322
Sulawesi with its peculiar K-shaped pattern is situated in an area where the Eurasian, Indian—Australian and Pacific plates interact and collide.Complex geological processess in this area resulted in the transformation of a normal island-arc structure into an inverted one, deformation of an already tectonized belt, sweeping of fragments against unrelated terrain, thrusting of oceanic and mantle material over the island arc, closing of deep-sea basins behind the arc, trapping of old oceanic crust caused by the rolling up of an island arc, formation of a marginal basin by the spreading of the sea floor behind the arc, development of small subduction zones with reverse polarities etc.Small deep-sea basins surrounding Sulawesi such as the Gulf of Bone and the Gulf of Gorontalo originally formed the arc—trench gap of the Sulawesi island arc.The Banda Sea is considered as an oceanic crust trapped by the bending of the east—west trending Banda arc due to the northward drift of Australia combined with the westward movement of the Pacific plate. Similarly the Sulawesi Sea consists of an old Pacific crust trapped by the westward bending of the Sulawesi island arc, caused by the spearheading westward thrust along the Sorong transform-fault system, in which later a minor spreading center became active in its central part. The Molucca Sea comprises tectonic mélange in which presumably a small spreading center developed between the two colliding arcs of northern Sulawesi and western Halmahera. While the Benioff zones dip under the northern Sulawesi and Halmahera arcs in normal fashion, the mélange thrusts over them. The Strait of Makassar is a marginal basin which was brought into existence by the spreading of the sea floor between Kalimantan and Sulawesi.The evolution of Sulawesi started in Miocene time or even earlier when 800 km east of Kalimantan a north—south trending east-facing island arc came into existence, originating from a spreading center located in the Pacific Ocean. Volcanism and plutonism accompanied this subduction process.Collision between Sulawesi and the Australian—New Guinea plate which occurred in early Pliocene time severely transformed Sulawesi into an island with its convex side turned towards the continent, at the same time causing obduction of ophiolite in the eastern arc of this island.The movement of the Pacific plate continued and gradually pushed Sulawesi towards the Asian continent, resulting in the closing of the sea between Kalimantan and Sulawesi islands separated by small straits and deep seas resembling the complicated pattern of the Philippine Archipelago, in which the original double island-arc structure can no longer be recognized. 相似文献
14.
深震等深线加深的梯度方向,反映了板块插入方向和板块俯冲力作用的主体方向;等深线凸进方向的动态变化,反映了贝尼奥夫带的偏转;日本海深源地震和我国东部地区浅震的个体(强震)和群体迁移,反映了深、浅部应力场强区的转移。这种转移的深层原因,可能与上地幔物质流流动方向变化有关。强区范围的圈定和转移规律,对地震的地点预报,具有重要意义。 相似文献
15.
The East China Sea Shelf Basin is an important oil- and gas-bearing basin in the West Pacific continental margin. This region was affected by subduction of the Pacific Plate and the Philippine Plate in Cenozoic and experienced multi-stage tectonic inversions. This paper presents results from a numerical simulation by finite element method to the Xihu Sag in the East China Sea Shelf Basin and neighboring areas in an attempt to evaluate the WNW-directed compression on the sag during Late Miocene. Based on comprehensive structural analysis of a large number of seismic profiles, we determine the structural geometry of the sag, including the basement of the basin, the sedimentary cover, and 29 major faults in the Xihu Sag. Simulation results show that under continuous WNW-directed compression, tectonic inversion occurred firstly in the Longjing and Yuquan tectonic zones in the sag. Based on quantitative analysis of vertical displacement field of the Xihu Sag and peripheral areas and its stress intensity evolution, we identify a compressional regime in the Longjing Anticline Zone with a gradually propagated uplifting from south to north; whereas the propagation of uplifting in the Yuquan Anticline Zone is from north to south. The inversion intensity decreases from north to south. The formation of the tectonic inversion zone in the Xihu Sag is not only correlated to the direction of compression and fault patterns in the basin, but also closely related to the spatial configuration of fault surfaces of the Xihu–Jilong Fault in the Xihu Sag. 相似文献
16.
The within-Iranian backarc basins, including the largest Sebzawar Basin, opened in the Mid-Cretaceous. Spreading in this basin
was completed by the end of the Cretaceous. The basin closed in the Eocene with the formation of subduction zones and volcanic-plutonic
belts. Data on North Afghanistan and the Central Pamirs have allowed us to reconstruct the eastern continuation of the Sebzawar
Basin up to the west of the Central Pamirs. No fragments of oceanic crust are retained in Afghanistan and the Pamirs, but
by analogy with the Sebzawar Basin, thick Paleogene flysch sequences and volcanic-plutonic complexes indicate setting of the
active margin and subduction. It is suggested that the belt of mantle seismicity that extends for 550 km to the south of the
Central Pamirs is related to the plunging and deformation of the lithosphere once underlying the Cretaceous-Paleogene basin.
The extremely vigorous seismicity of the Hindu Kush megasource at the western termination of the seismic belt is caused by
a number of specific tectonic features that predetermined the early onset of plunging of the subducted sheet (slab). In the
megasource, the slab sank to a depth of 300 km and became vertical; its active deformation has proceeded up to the present.
In the eastern part of the seismic belt, the slab started to plunge much later and therefore has retained a gentle slope,
so that the depth of the hypocenters is shallower (down to 200 km), and earthquakes are less strong. 相似文献
17.
华北地块南部巨型陆内俯冲带与秦岭造山带岩石圈现今三维结构 总被引：44，自引：1，他引：44
豫西横穿秦岭造山带的反射地震为主的综合地球物理探测，发现秦岭现今北界存在华北地块南部自北向南向秦岭的巨型陆内俯冲带，深达Ｍｏｈｏ面以下，与之相伴而生，在中上地壳发育自南向北的逆冲推构造带，千公里东西向延伸，主要发生于晚白垩世１００Ｍａ±，成为秦岭与华北地区块间中新生代重要陆内构造，它是秦岭造山带岩石圈现今三维结构的基本要素和组成部分，秦岭造山带岩石圈现今结构具有流变学分层的“立交桥”三维结构框架模型。显然它们具有统一的动力学背景，是秦岭造山带现今处于印度－青藏、太平洋和欧亚板块的西伯利亚地块等三大构造动力学体系复合部位，导致其从深部地幔动力学的最新调整到上部地壳响应所发生的壳幔等圈层相互作用的综合产物，可能是大陆长期保存、演化的主要途径与形式之一，具有重要的大陆动力学意义，对中国大陆构造、灾害、环境研究也具重要意义。 相似文献
18.
The results of detailed seismological observations with bottom recording systems carried out in 2004 and 2006 near the Dagestan coast of the Middle Caspian are considered. The records of more than 550 micro- and weak earthquakes with ML = 0.1–4.7 (MLH = ?0.7 to 4.3) were obtained during 165 days of recording; a fifth of these earthquakes occurred in the upper mantle at a depth of 50–200 km. Over the entire period of instrumental recording since the 1930s, only 10 mantle earthquakes with MLH = 3.5?6.3 have been recorded by on-land systems. The highest density of earthquake epicenters with source depths down to 50 km is established on the Middle Caspian coast between Derbent and Izberbash and in the adjacent water area. The mantle earthquakes with hypocenters at a depth of 60–80 km cluster beneath the western wall of the Derbent Basin, whereas deeper hypocenters are located beneath both the wall of this basin and the Middle Caspian coast. The sporadic mantle earthquakes recorded in 2004 (about 30 shocks), determined by a network of systems with a small aperture, depicted a zone plunging beneath the Greater Caucasus with indications of a peculiar “subduction” of the Scythian Plate beneath the Caucasus. Subsequent observations based on a more extensive network were carried out in 2006. They substantially changed the pattern of mantle earthquake hypocenters. According to this evidence, the sources of mantle earthquakes make up a dispersed cloud extended in the vertical direction beneath the Middle Caspian coast and water area, which may be regarded as a relic of tectonic activity of a bygone tectonic epoch. A comprehensive tectonic interpretation of the detected seismological phenomenon is given. 相似文献