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中国川西地区鲜水河断裂和则木河断裂几何学,运动学特征及地震活动性对比 总被引：2，自引：0，他引：2
鲜水河断裂与则木河断裂在几何学特征、运动学特征和地震活动方面既有明显的相似之处，又有着重要的差别，由于这两条断裂带都位于川滇菱形块体的北东边界，同属川西巨型左旋走滑断裂带的组成部分，因此在断裂的几何格局、活动方式和地震活动等方面有许多相似之处，然而，在菱形块体自北西向南东方向运动的过程中，由于其东部受到四川地块的阻挡使得块体边界的位移呈现由北西向南东递减的趋势，进而造成了两条断裂带在地震活动性方面 相似文献
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根据卫星影像解译和野外调查结果,本文重点分析研究楚雄-南华断裂的活动特征、最新活动时代、第四纪盆地的成因以及与1680年楚雄 6?级地震的关系。吕合、南华等多处第四纪断层剖面揭示了断错龙川江Ⅱ、Ⅲ级阶地晚更新世晚期堆积,表明该断裂是一条晚第四纪活动断裂,其最新时代为晚更新世晚期乃至全新世,运动性质以右旋走滑运动为主,水平走滑速率1.6～2.0mm/a。沿断裂发育有楚雄、南华、子午等多个第四纪拉分盆地。历史上,断裂附近曾发生1680年楚雄 6?级地震和多次中强地震,楚雄-南华断裂为这些地震的发震构造。从更大区域范围看,它与东部的曲江断裂、石屏-建水断裂一起,构成一组斜列的右旋走滑为主的活动断裂带。这种运动学特征类似于川滇菱形块体西南边界的红河断裂带,与川滇菱形块体SE向逃逸(运动)有关。 相似文献
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《中国地震》2015,(3)
根据卫星影像解译和野外调查结果,本文重点分析研究楚雄-南华断裂的活动特征、最新活动时代、第四纪盆地的成因以及与1680年楚雄6(3/4)级地震的关系。吕合、南华等多处第四纪断层剖面揭示了断错龙川江Ⅱ、Ⅲ级阶地晚更新世晚期堆积,表明该断裂是一条晚第四纪活动断裂,其最新时代为晚更新世晚期乃至全新世,运动性质以右旋走滑运动为主,水平走滑速率1.6~2.0mm/a。沿断裂发育有楚雄、南华、子午等多个第四纪拉分盆地。历史上,断裂附近曾发生1680年楚雄6(3/4)级地震和多次中强地震,楚雄-南华断裂为这些地震的发震构造。从更大区域范围看,它与东部的曲江断裂、石屏-建水断裂一起,构成一组斜列的右旋走滑为主的活动断裂带。这种运动学特征类似于川滇菱形块体西南边界的红河断裂带,与川滇菱形块体SE向逃逸(运动)有关。 相似文献
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1 研究背景
川滇菱形块体是青藏高原东缘侧向挤出最强的活动块体,地震活动强烈而频繁.其西南边界——红河断裂带是一条右旋走滑的活动断裂,其西北边界——金沙江断裂是一条多期活动的缝合线构造,表现为右旋走滑兼逆冲性质.维西—乔后断裂位于川滇菱形块体西部边缘,南与红河断裂相接,北与金沙江断裂相连,是红河活动断裂带的北延部分(图1). 相似文献
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北西向张家口－蓬莱断裂带由近２０条北西至北西西向断裂组成,是一条对新生代区域地质构造发育起到重要控制作用的地壳构造带。断裂带新生代活动由中部向西北和东南部发展,总体表现左旋走滑性质。断裂带有山西断陷盆地带等几条北东向活动构造带与之交汇,形成北西和北东向两组断裂相互交切的构造组合,出现５个复杂的构造交接段。６级以上强震和大多数中小地震群集于这些地段,其中北西和北东向断裂都可能发生地震,显示共轭破裂错动特征,但北东向断裂发生的地震强度较大。张北－尚义６．２级地震发生于断裂带与山西断陷盆地带交接段的西缘,是断裂带向西北扩展的结果 相似文献
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下热尔断裂位于巴颜喀拉块体东北边界变形带即东昆仑断裂带东段与迭部-白龙江断裂2条剪切断裂之间挤压变形带内,在空间上属于“玛曲空段”范围.经野外考察及遥感资料验证,确定下热尔断裂走向为310°,长度约为20km,运动学特征表现为左旋走滑为主兼少量倾滑分量,沿断裂发育大量断错地貌,水平位移主要分布在3.5～5m,而未发现垂向断错地貌;垂直断裂走向开挖2处探槽,揭示断层切穿晚第四纪地层,被地表沼泽相泥炭层覆盖,结合相关地层年龄资料,初步得出平均水平滑动速率约为6.3mm/a.该断裂在几何学与运动学方面与东昆仑断裂带具有较好的一致性,推测两者之间存在一定相关性,属于东昆仑断裂带走滑断裂体系内的一条次级断裂或过渡性断裂. 相似文献
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The Chi‐Chi earthquake (MW = 7.6) took place in central western Taiwan in 1999. The earthquake caused reactivation of the Chelungpu Fault and resulted in 100‐km‐long surface ruptures. The fault strikes mostly north–south to NNE–SSW; however, the northern tip of the southern segment of the surface ruptures rotates clockwise to define an east–west trend, then jumps to a shorter NNW‐trending rupture. The largest vertical displacement is recorded in the Shihkang area of the Shihkang–Shangchi Fault Zone, where vertical slips are up to 8–10 m. The Shihkang–Shangchi Fault Zone displays a complex fault pattern as a linkage damage zone between two fault segments with the greatest concentration of faults and fractures. Our new interpretation, based on recent published geometric, kinematic, and geophysical studies on the Chi‐Chi earthquake fault, suggests that the Shihkang–Shangchi Fault Zone is not a simple termination zone, but may be an ‘overstep zone’ or a ‘transfer zone’. Slip analysis along the surface ruptures indicates that they are composed of three fault segments and the amount of slip partly depends on the intersection angle between slip direction and fault strike. Our numerical modeling for the area indicates that Coulomb stress changes are mainly concentrated on tips and bends of the surface ruptures. Slip patterns indicate that the fault propagates toward the northeast. Therefore, this study suggests high potential for future earthquake activity along the unruptured Shangchi segment. Hence, future geohazard studies should focus on the Shangchi segment to evaluate potential earthquakes, determine recurrence intervals, and reduce future earthquake hazards. 相似文献
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Koichiro Fujimoto Hidemi Tanaka Takayuki Higuchi Naoto Tomida Tomoyuki Ohtani Hisao Ito 《Island Arc》2001,10(3-4):401-410
Abstract Mineralogical and geochemical studies on the fault rocks from the Nojima–Hirabayashi borehole, south-west Japan, are performed to clarify the alteration and mass transfer in the Nojima Fault Zone at shallow depths. A complete sequence from the hornblende–biotite granodiorite protolith to the fault core can be observed without serious disorganization by surface weathering. The parts deeper than 426.2 m are in the fault zone where rocks have suffered fault-related deformation and alteration. Characteristic alteration minerals in the fault zone are smectite, zeolites (laumontite, stilbite), and carbonate minerals (calcite and siderite). It is inferred that laumontite veins formed at temperatures higher than approximately 100°C during the fault activity. A reverse component in the movement of the Nojima Fault influences the distribution of zeolites. Zeolite is the main sealing mineral in relatively deep parts, whereas carbonate is the main sealing mineral at shallower depths. Several shear zones are recognized in the fault zone. Intense alteration is localized in the gouge zones. Rock chemistry changes in a different manner between different shear zones in the fault zone. The main shear zone (MSZ), which corresponds to the core of the Nojima Fault, shows increased concentration of most elements except Si, Al, Na, and K. However, a lower shear zone (LSZ-2), which is characterized by intense alteration rather than cataclastic deformation, shows a decreased concentration of most elements including Ti and Zr. A simple volume change analysis based on Ti and Zr immobility, commonly used to examine the changes in fault rock chemistry, cannot account fully for the different behaviors of Ti and Zr among the two gouge zones. 相似文献
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郯庐断裂带东地堑边界断层在断裂带演化过程和现今构造格局中都是重要断层,对该边界断层的第四纪活动性研究有助于了解郯庐断裂带的演化历史和地震活动性,而有关该边界断层第四纪活动性研究较少且至今尚无定论。本文通过浅层地震勘探和钻孔联合剖面相结合的方法,针对郯庐断裂带江苏段东地堑两边界断层开展系统的断层第四纪活动性研究,结果显示,昌邑-大店断裂(F_1)第四纪以来未见构造运动证据,白芬子-浮来山断裂(F_2)在第四纪早期曾发生有关活动,晚更新世以来未见活动迹象。 相似文献
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我国东南沿海滨海断裂带是1条活动强烈的地震构造带，位于珠江口盆地北缘的粤东滨海断裂带是其重要组成部分，确定该断裂带的几何展布位置与最新活动特征对科学评价华南沿海地区地震危险性、地震构造和地球动力学具有重要科学意义。通过综合分析近年来南海东北部海域地质地貌、地震反射剖面、深部探测、地震活动等方面的研究成果，总结了粤东滨海断裂带几何结构与分段活动性，研究成果已应用于粤东沿海重大工程选址和地震区划工作中。 相似文献
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利用GIS方法研究南北地震带和中央造山带交汇区活动断裂与地震的关系 总被引：3，自引：1，他引：2
基于地理信息系统(GIS)技术研究南北地震带和中央造山带交汇区断裂带分布与地震活动的关系,对区内16条主要断裂带,以25km为缓冲区宽度,进行叠加,分析各断裂带的地震活动性及其特征.结果表明,主要的发震断裂有西秦岭北缘断裂的西段、礼县-罗家堡断裂西南段以及临潭-宕昌断裂的东南段、文县断裂西南段、虎牙断裂和雪山断裂;虎牙断裂和雪山断裂地震活动性最强,其次是塔藏断裂、礼县-罗家堡断裂以及光盖山-迭山北麓断裂;按震源深度可将研究区划分为4个区域,区内的震源深度由北向南逐渐加大,震源深度剖面图反映了断层的几何形态和力学性质,进一步揭示出了青藏高原向东挤压、物质向东向南逃逸的运动模式. 相似文献
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Tomoyuki Ohtani Hidemi Tanaka Koichiro Fujimoto Takayuki Higuchi Naoto Tomida Hisao Ito 《Island Arc》2001,10(3-4):392-400
Abstract The internal structures of the Nojima Fault, south-west Japan, are examined from mesoscopic observations of continuous core samples from the Hirabayashi Geological Survey of Japan (GSJ) drilling. The drilling penetrated the central part of the Nojima Fault, which ruptured during the 1995 Kobe earthquake (Hyogo-ken Nanbu earthquake) ( M 7.2). It intersected a 0.3 m-thick layer of fault gouge, which is presumed to constitute the fault core (defined as a narrow zone of extremely concentrated deformation) of the Nojima Fault Zone. The rocks obtained from the Hirabayashi GSJ drilling were divided into five types based on the intensities of deformation and alteration: host rock, weakly deformed and altered granodiorite, fault breccia, cataclasite, and fault gouge. Weakly deformed and altered granodiorite is distributed widely in the fault zone. Fault breccia appears mostly just above the fault core. Cataclasite is distributed mainly in a narrow (≈1 m wide) zone in between the fault core and a smaller gouge zone encountered lower down from the drilling. Fault gouge in the fault core is divided into three types based on their color and textures. From their cross-cutting relationships and vein development, the lowest fault gouge in the fault core is judged to be newer than the other two. The fault zone characterized by the deformation and alteration is assumed to be deeper than 426.2 m and its net thickness is > 46.5 m. The fault rocks in the hanging wall (above the fault core) are deformed and altered more intensely than those in the footwall (below the fault core). Furthermore, the intensities of deformation and alteration increase progressively towards the fault core in the hanging wall, but not in the footwall. The difference in the fault rock distribution between the hanging wall and the footwall might be related to the offset of the Nojima Fault and/or the asymmetrical ground motion during earthquakes. 相似文献
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On the basis of comprehensive analyses of fault textures and geometry, the active methods, stress field, mechanism and time of the Yishu Fault Zone during the neotectonic period are discussed in this paper. The results show that the Yishu Fault Zone is a major mobile belt since the Quaternary. It consists of four major active faults with reverse dextral slip. Their active intensity increases eastwards and southwards. Fault-slip data from many active faults in the fault zone demonstrate that ENE-WSW compression predominated in the neotectonic period. Detailed field investigation shows that formation mechanism of shallow, active faults in the Yishu Fault Zone includes direct boundary fault reactivity, buried fault propagation, and reactivity of antithetic and truncating faults. In most cases, shallow, active faults in the fault zone are developed through direct reactivity or upward propagation of the previous four graben boundary faults. 相似文献
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郯庐断裂带莱州湾段的构造特征 总被引：5，自引：1，他引：5
本文利用海上浅层地震勘探剖面分析了郯庐断裂带莱州湾段的上更新统、全新统和活动构造的某些特征。晚更新世末期发生的构造运动使上更新统产生断裂与褶皱,沿郯庐断裂带东主干断裂发育了狭长的背斜构造,在西主干断裂两侧次级横向(东西向)断裂十分发育,这些横向断裂是一些高角度的张性正断层。 相似文献
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Miroslav Novotný 《Surveys in Geophysics》2012,33(2):243-273
In the accompanying paper (Part A), depth-recursive tomography was applied to the CEL09 refraction data. A deblurred P-wave velocity image was obtained down to a depth of 20 km. This paper (Part B) is devoted to the interpretation of the upper- and middle-crustal structures of the Bohemian Massif imaged in the CEL09 section. Because of inherent ambiguity of the refraction method in imaging low-velocity zones, other well-known results based on other geophysical data sets are also used to independently verify the interpreted velocity features. Comparison with the density and velocity models previously obtained indicates that the presented P-wave velocity image has superior resolution revealing or verifying a number of geological features. The prominent lateral velocity changes encountered in the CEL09 pattern across the imaged crustal section were used to delineate the main terranes and deep regional fault zones such as the Kru?né hory Fault, the SW continuation of the Litomě?ice Fault Zone, the West and Central Bohemian Shear Zones, the Blanice-Rodl Fault, the P?ibyslav-Vitis Fault and the Boskovice-Diendorf Fault. The 450-km-long CEL09 transect reveals seven major deeply rooted high-velocity (HV) anomalies identified as Variscan massifs intruded near or within these deep fault zones. They form buried ridges mostly parallel to the SW-NE trending Variscan strike. Their discovery allows new insights into a number of phenomena such as the West Bohemian earthquake swarms, the Saxothuringian paradox, the character of the Saxothuringian-Barrandian contact zone, the detachment surface due to the slab of the Saxothuringian crust subducting beneath the Teplá-Barrandian zone in the Devonian, the depth extent of the Mariánské-Lázně Complex (MLC) as an equivalent unit of the Zone Erbendorf-Vohenstrauss (ZEV), the subsidence of the Barrandian syncline, the root zones of the Central and South Bohemian Plutons, the accretionary wedge formed along the Moravo-Moldanubian suture and its link with the Gföhl terrane, the Carpathian foreland relief and the subsidence observed in the Vienna Basin. 相似文献
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Derived gravity field of the seismogenic upper crust of SE Germany and West Bohemia and its comparison with seismicity 总被引：2，自引：2，他引：0
The gravity field of the seismogenic upper crust was derived from the Bouguer gravity map by applying the Butterworth high-pass
filter in the wave-number domain. The cutoff wavelength of the filter was 110 km, to pass the gravity signals of structures
within the 18 km thick seismogenic layer. The derived residual gravity map reveals potential stress concentrating structures,
which may cause seismicity provided they lie within the existing zones of weakness. Furthermore we derived a shaded relief
map of the horizontal gravity gradient, which highlighted the tectonic lines accompanied by density contrast. The directional
analysis of this map shows three dominant strike directions. The most prominent one is “the Hercynian” NW-SE strike direction
represented by the Franconian Line, the Gera-Jáchymov Fault Zone and the Elbe Zone. The second dominant strike is the Rhenisch
NNE-SSW trending represented by the Upper Rhine Graben Zone, Rheinsberg-Heldburg Line and several Proterozoic volcanic belts
in the Teplá-Barrandien Unit. The third pronounced trending of the ENE-WSW direction is represented by the Erzgebirge and
Eger Graben gravity low. The N-S trending Rostock-Leipzig-Regensburg Zone (Pritzwalk-Naab Lineament) is not distinctly reflected
in the derived gravity maps, although many fault segments have a meridian direction.
The relative reactivation potential of some pre-existing fault systems identified in the gravity map was studied with respect
to the wide range of the recent stress configuration determined in the West Bohemia/Vogtland region. The resulting diagrams
show that the steep NNW-SSE to N-S faults (represented by some segments of the Mariánské Lázně Fault Zone) are oriented favourably
for reactivation. On the contrary, the orientation of the ENE-WSW faults limiting the Eger Graben (Litoměřice Fault, etc.)
is unfavourable for reactivation for all dip values. 相似文献