共查询到20条相似文献，搜索用时 140 毫秒
1.
福建漳州盆地岱山岩—珩坑北西向断裂带第四纪活动特征 总被引：4，自引：0，他引：4
通过对岱山岩-珩坑北西向断裂两侧第四纪地层的分布、构造地貌的发育等资料的分析，着重研究了该断裂带第四纪的活动特征，并探讨了活动断裂与地震活动的关系，研究结果表明：该断裂带是一条第四纪以来垂直正断兼具左旋水平走滑的活动断裂，在时间上断裂活动具有多期性；在空间上断裂活动具有迁移性；并在断裂的延伸方向存在差异活动而具有分段性，该断裂带第四纪以来宏观活动性和现今垂直形变活动性明显，1445年在该断裂最具活动的地段发生61/4级地震，表明该断裂现今仍在继续活动，今后仍有发生中强破坏性地震的可能。 相似文献
2.
太行山山前断裂位于太行山脉与华北平原过渡地带,是华北及我国东部地区一条重要的构造带,有关该断裂带的活动性有以下观点:1)它属深大断裂带;2)它是活动断裂带和地震构造带;3)它不是地震构造带。。为研究和评价该断裂的活动性,利用最近获得的地震资料和钻探联合剖面研究了太行山山前断裂的深部构造背景和第四系以来的活动特征。钻探验证以及研究结果与表明:太行山山前断裂不是岩石圈深大断裂,该断裂在第四系仅错断了中更新世QP2早期,中更新世QP2晚期和晚更新世地层没有发生错断。由此得出,太行山山前断裂不是活动断裂,也不是岩石圈深大断裂。该研究结果为跨越太行山山前断裂的城市进行规划和建设提供了重要的地质和地球物理资料,对于首都圈地震危险性评价也具有十分重要的意义。 相似文献
3.
通过对1971年以来福建政和-海丰断裂地震活动特征分析,认为政和-海丰断裂的地震活动是:在主体北东向政和-海丰断裂带和次级北西向永安-晋江断裂带相互交汇的构造格局下,形成了4～5级中强地震反复发生的潜在震源区. 相似文献
4.
盐关河北东东向活断裂晚更新世以来活动性很强,长期保持着左错构造运动,水平幅度大,平均左行滑动速率为5mm/a。80km地震破裂形变带的分布是其最新活动的地质标志,断错微地貌构造特征显著。活断裂带上古地震遗迹的发掘也印证了全新世以来该断裂经历了多次强地震活动。全新世早期是盐关河断裂活动的全盛期,强震活动属分散结点发震类型。盐关河断裂的破裂发展受现今构造应力场N50°～60°E主压应力方向的控制,与1654年罗家堡8级地震有成因关系。研究认为:交叉破裂为发震机制;稠泥河北北西向与盐关河北东东向活断裂交叉复合为发震构造的背景;北北西向喇糜隆起带为控震构造。 相似文献
5.
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
6.
7.
据近年来的地质和地球物理资料对太行山山前断裂带做了研究 ,得到一些新的认识。断裂带开始出现于中生代 ,主要形成于早第三纪 ,由一系列NE -NNE向断裂左型斜列组成。断裂带的结构构造和活动具有鲜明的分段性 ,中北段的保定 -石家庄等断裂为大型拆离断裂 ,在倾向上水平延伸 70km左右 ,早第三纪水平拉张断距约 17km ,垂直断距 50 0 0～ 60 0 0m。断裂带基本上是发育于上地壳的拆离滑脱构造 ,不属深大断裂。它第四纪活动性不强 ,与强震活动没有直接成因关系 ,但断裂带南、北两部分与其它走向的地震构造带交汇 ,对区域地震构造和地震预测研究仍有重要意义 相似文献
8.
四川活动断裂带的基本特征 总被引：6，自引：0，他引：6
根据大量的实际资料，总结了四川活动断裂带的基本特征：即大致以北东向龙门山断裂带与北西向荣经－马边－盐津断裂带为界，显示了西强东弱的分区活动特点。断裂活动在时间、空间和强度上都具有明显的不均匀性与分段活动特征；晚更新世～全新世以来发生的强震破裂活动大都是沿袭先存断裂进行的，从古地震研究及较短时间尺度（有历史地震记录以来）来看，反映出断层上的位移是以一种地震构造脉冲形式出现 相似文献
9.
松潘—龙门山地区主要活动断裂带第四纪活动特征 总被引：31，自引：0，他引：31
本文主要根据我们近两年来对松潘—龙门山地区主要断裂带的野外调查成果,并参考前人资料,结合第四纪年代学和断层活动性与地震关系的研究,重点讨论了松潘—龙门山地区几条主要活动断裂带的第四纪活动特征。研究结果表明:这几条活动断裂带在中、晚更新世以来活动的强弱与其地震活动在时、空分布上的不均匀性有较好的一致性,即地震活动的强度、频度严格受断裂带在中、晚更新世以来的活动强度、活动方式的制约,强震主要发生在晚更新世以来断裂的最新活动段上。 相似文献
10.
龙门山构造带区域稳定性探讨 总被引：13，自引：0，他引：13
根据龙门山构造带的地震地质特征、地震活动规律及新构造活动特征,综合分析认为该地区区域稳定性受控于龙门山断裂带。而断裂带又以韧性切变形为主,蠕滑运动为特征,决定该带在相当长的一段时间内,发生强烈地震的可能性不大。 相似文献
11.
礼县 -罗家堡断裂带晚更新世以来有过明显活动。在礼县—罗家堡段和天水镇—街子口段直接错断全新世地层。断裂沿线地表陡坎发育 ,水系被左旋位错。结合沿该断裂带广泛分布的地震滑坡、砂土液化等 ,认为礼县 -罗家堡断裂带是 1654年天水南 8级地震的发震构造。该断裂晚更新世以来的平均水平位错速率为 0 95mm/a ,平均垂直位移速率为 0 35mm/a ,垂直位移速率约为水平位移速率的 1/ 3。这个比值与一次断裂突发性垂直位错量 ( 1 9m)与水平位错量 ( 5 2m)的比值基本吻合 相似文献
12.
利用区域GPS和水准测量资料，结合地震构造背景的分析，本文研究2008年汶川8.0级地震前横跨龙门山断裂带地区的震间地壳形变，探讨引起这种形变的活动构造与动力学模式，并由此认识汶川地震的孕育与成因机制.主要结果表明：1997～2007年期间，自龙门山断裂带中段朝北西约230 km的地带内存在垂直于断裂的水平缩短变形、以及平行于断裂的水平右旋剪切变形，缩短率为1.3×10-8/a （即：0.013 mm/km/a），角变形速率为2.6×10-8/a；同一地带在1975～1997年期间还表现出垂直上隆变形，上隆速率在龙门山前山断裂与中央断裂之间仅0.6 mm/a，而至龙门山后山断裂及其以西达2～3 mm/a.这些反映了在汶川地震之前至少10～30余年，龙门山断裂带中段的前山与中央断裂业已闭锁、并伴有应变积累.造成这种形变的主要原因是：以壳内的低速层为“解耦”带，巴颜喀拉地块上地壳朝南东的水平运动在四川盆地西缘受到华南地块的阻挡、转换成龙门山断裂带中段的逆冲运动；由于该断裂段的震间闭锁，致使西侧的巴颜喀拉地块的上地壳发生横向缩短以及平行断裂的右旋剪切变形.然而，龙门山断裂带北段在1997～2007年期间除了有大约0.9 mm/a的右旋剪切变形外，横向的缩短变形极微弱，这可能与该断裂段西侧的岷江、虎牙、龙日坝等断裂带吸收了巴颜喀拉地块朝东水平运动的大部分有关.另外，汶川地震前，横跨龙门山断裂带中段与北段的地壳形变特征的差异，与汶川地震时能量释放的空间分布吻合. 相似文献
13.
龙泉山构造带是四川盆地内川西强烈断陷区和川中稳定隆起区之间的一条区域性断裂.2008年汶川地震后该断裂带未来的强震潜势备受关注.本文对该断裂带的展布、晚第四纪活动性、深部构造形成机制以及断裂带未来的地震危险潜势进行了讨论.断裂带北段位于德阳东侧龙泉山脉西缘;龙泉山脉中段的山体两翼存在断裂;断裂带的南段以向西倾斜的断裂为主.这些断裂在晚更新世以来曾有活动,前人阶地调查显现该断裂带全新世存在活动.考虑到该断裂带未来的地震潜势评估,值得对该断裂带的活动性及断裂带深部构造和运动方式开展进一步的调查. 相似文献
14.
作者通过对区域地质调查资料的分析研究和实地考察,对金沙江断裂带的展布范围进行了划分,认为金沙江断裂带是川西规模巨大的断裂带,从地震活动、断裂地貌特征、水系扭曲、第四纪地层形变和温泉沿断裂分布等表明它是一个活动断裂带。通过对历史地震实地访问调查,获得了1923年巴塘6.5级地震的震害情况,并发现了这次地震在地表所产生的地裂缝,从而确定了这次地震的宏观震中位置,探讨了地震与断裂的关系。无疑对金沙江断裂带活动性的认识、地震预报和地震烈度区划工作具有现实意义。 相似文献
15.
中卫—同心断裂带西段位于宁夏中卫县甘塘附近,在近期的某重大工程场地的区域地震地质野外调查中,经过断层陡坎和断错冲沟等微地貌测量、槽探揭露、年代样品的采集和测定,获得了断层最新活动时代、活动方式、垂直和水平位移量等资料,表明了它在晚第四纪以来的活动特征。 相似文献
16.
1985年乌恰7.4级地震在克孜勒苏河谷阶地上出现地表形变带,主要由地震陡坎、地震断层、地裂缝与挤压脊等形迹组成。长约15公里,最宽达800米。分布形态为一向东北突出的弧形形变带。逆断层走向近东西,倾向160°—210°,倾角30°左右,最大水平倾向断距约2米。正走滑断层走向340°—350°,倾向北东,倾角80°—88°,最大右旋水平位错为1.55米。走滑逆断层走向为280°—305°。倾向西南,倾角30°左右,最大右旋水平位移1.25米。挤压脊多呈东西向分布,最大缩短距离为0.4米 相似文献
17.
TYPE AND DISPLACEMENT CHARACTERISTICS OF LINGSHAN M6¾ EARTHQUAKE SURFACE RUPTURE ZONE IN 1936, GUANGXI 
下载免费PDF全文
下载免费PDF全文 LI Xi-guang PAN Li-li LI Bing-su NIE Guan-jun WU Jiao-bing LU Jun-hong YAN Xiao-min 《地震地质》2017,39(5):904-916
On April 1, 1936, an M6¾ earthquake occurred on the Fangcheng-lingshan Fault. So far, the Lingshan M6¾ earthquake is the biggest one in South China. There are some reports about the Lingshan earthquake fissures, but its surface rupture hasn't been systemically studied. Based on the geological mapping and measurement of the right-lateral displacement and vertical offset, the surface rupture zone caused by the Lingshan M6¾ earthquake was found, which contains two secondary surface rupture zones in the east and west respectively, its strike varies from N55°E to N60°E with en echelon-like distribution along the north section of Lingshan Fault, and its total length is about 12.5km. The western surface rupture zone locates intermittently along Gaotang-Xiatang-Liumeng, about 9.4km in length, with a right-lateral displacement of 0.54~2.9m and a vertical offset of 0.23~1.02m; the other one appears between Jiaogenping and Hekou, about 3.1km in length, with a right-lateral displacement of 0.36~1.3m and a vertical offset of 0.15~0.57m. The maximum right-lateral displacement and vertical offset are 2.9m and 1.02m, appearing at the east of Xiatang reservoir. The types of surface rupture mainly contain earthquake fault, earthquake scarp, earthquake fissure, earthquake colluvial wedge, earthquake caused landslide and liquefaction of sand and so on. The earthquake fault develops at the east of Xiatang and Jiaogenping, earthquake scarp appears at Xiaoyilu and Xiatang, earthquake fissure locates at Xiatang, there are multiple earthquake landslides along the surface rupture zone, and the trench LSTC03 exposes the earthquake colluvial wedge. In order to further investigate the Lingshan earthquake surface rupture zones, the author compares the parameters of Lingshan M6¾ earthquake with the similar typical earthquakes in western China, the results show that the parameters of Lingshan earthquake are similar to the typical earthquakes in western China. The length of Lingshan earthquake surface rupture is shorter, but the dislocation is bigger. The author considers that this is mainly related with the parameters of Lingshan earthquake, site condition and structural environment of surface rupture zone, the symbols of dislocation measuring, human activity and weather condition and so on. The research of surface rupture zone features and analysis of Lingshan M6¾ earthquake provides important and basic data for exploring the seismogenic structure of Lingshan M6¾ earthquake, and it has important scientific significance. 相似文献
18.
The southeast section of Zhongdian-Daju Fault is located in the northern part of Haba and Yulong Snow Mountain, belonging to the southwestern boundary of the secondary block in northwestern Sichuan, an important boundary fault striking 310°~320° on the whole. The nature of the fault, the age of its activity and the slip rate are of great significance for the analysis of the secondary block movement in the northwestern Sichuan and the intersection relationship with the eastern piedmont fault of Yulong Mountains.
Based on the 1 ︰ 5 million-scale active fault geological mapping, this paper studies in detail the stratigraphic landform, scarp landform, surface rupture, typical fault profile and river terrace along the fault. Based on the research results, we divide the southeastern section of Zhongdian-Daju Fault into two sub-segments, the Majiacun-Daju sub-segment and the Daju-Dadong sub-segment, according to the geometric structure, fault landforms and fault activity.
(1)Fault scarp:In the Majiacun-Daju sub-segment, the fault parallelly controls the two sides of the Haba fault depression. It cuts the late Pleistocene moraine deposits, forming a fault scarp of about 4.5km long and(14±2)m high. The continuity of the scarp is very good, and it is also very obvious in the remote sensing image. In the Daju-Dadong sub-segment, a scarp with a height of about 2m is formed, and an optical luminescence dating sample is collected from the upper part of the gravel layer on the second-order terrace to obtain an age of(22±2.2)ka.
(2)Horizontal dislocation:In the Majiacun-Daju sub-segment, through the analysis of the development of outwash fans in the area and the measurement and induction of the gully dislocations, it is considered that there are at least three stages of outwash fans developed in the area and there may be four phases of faulting. That is, the earliest-stage outwash fan and gully are horizontally dislocated about 1km; the second-stage outwash fan and gully are horizontally dislocated about 47m, and the vertical dislocation is about(14±2)m; the gully in the third stage outwash fan is horizontally dislocated twice, the first dislocation formed a beheaded gully with a dislocation of 22m, and the second formed a beheaded gully with a dislocation of 8.5m. It is further proved that the fault has strong activity since the Holocene in the Majiacun to Daju area. In the Daju-Dadong sub-segment, there are no obvious horizontal dislocations in the alluvial deposits since the Holocene. Only 3~4 gullies are found to be offset right-laterally in the ridges east of Wenhe Village, with the maximum dislocation of 210m, which may be the older phase dislocation.
(3)Surface rupture:In the northwest direction of Dabazi Village on the T3 terrace in the basin between Majiacun and Daju, an earthquake surface rupture zone is found, extending in the NW direction. The rupture zone left clear traces on the about 1m-thick, hard T3 terrace surface formed by calcification of sand gravels, and the overburden either upwarps and bulges, or ruptures, generates ground fissures, or forms small pull-apart "depressions" locally. However, the rupture zone is not large in size, about 350m long, 60m wide at the widest point, and 0.3~1.5m high. It is partially en-echelon or obliquely arranged, dominated by compressive ruptures. Through observation, the possibility of artificial transformation is ruled out for these upwarping bulges, ruptures or ground fissures. The fault section is found in the southeast direction of the rupture zone. The slickensides at the section show that the fault is dominated by right-lateral strike-slip with a small amount of thrust. In the eastern sub-segment, only intermittently distributed surface ruptures are found in the northern part of the village, and the scale is small.
In summary, through the field geological survey, it is found that the Majiacun-Daju sub-segment is a Holocene active segment. Though the Daju-Dadong sub-segment also offset the late Pleistocene to Holocene strata, it is considered that its Holocene activity is weak in terms of either the dislocation amount or the slip rate of this segment.
By analyzing the geological and geomorphological evidences, such as fault scarps, horizontal dislocation and surface ruptures along the fault, it is considered that the Majiacun-Daju sub-segment is a right-lateral strike-slip fault with a normal faulting component, and its vertical slip rate since the late Pleistocene is(0.4~0.8)mm/a, the horizontal slip rate is 1.5~2.4mm/a. The Daju-Dadong sub-segment is dominated by right-lateral strike-slip with a normal faulting component, and its vertical slip rate since the late Late Cenozoic is 0.1mm/a.
The formation of the NW-trending surface rupture zone found in the Daju Basin is very young, where there are only two major earthquakes, namely, the MS6.4 1966 Zhongdian earthquake and the 1996 Lijiang MS7.0 earthquake, and both earthquakes produced NW-oriented surface rupture zones. Therefore, it cannot be ruled out that the rupture zone is a product of the 1966 Zhongdian MS6.4 earthquake or the 1996 Lijiang MS7.0 earthquake. 相似文献
19.
LATE QUATERNARY ACTIVITY OF THE CENTRAL SEGMENT OF THE DARI FAULT AND RESTUDY OF THE SURFACE RUPTURE ZONE OF THE 1947 M73/4 DARI EARTHQUAKE,QINGHAI PROVINCE 下载免费PDF全文
下载免费PDF全文 Bayan Hara Block is one of the most representative active blocks resulting from the lateral extrusion of Tibet Plateau since the Cenozoic. Its southern and northern boundary faults are characterized by typical strike-slip shear deformation. Its eastern boundary is blocked by the Yangze block and its horizontal movement is transformed into the vertical movement of the Longmen Shan tectonic belt, leading to the uplift of the Longmen Shan Mountains and forming a grand geomorphic barrier on the eastern margin of the Tibet Plateau. A series of large earthquakes occurred along the boundary faults of the Bayan Hara Block in the past twenty years, which have attracted attention of many scholars. At present, the related studies of active tectonics on Bayan Hara Block are mainly concentrated on the boundary faults, such as Yushu-Ganzi-Xianshuihe Fault, East Kunlun Fault and Longmen Shan Fault. However, there are also some large faults inside the block, which not only have late Quaternary activity, but also have tectonic conditions to produce strong earthquake. These faults divide the Bayan Hara Block into some secondary blocks, and may play important roles in the kinematics and dynamics mechanism of the Bayan Hara Block, or even the eastern margin of the Tibet Plateau. The Dari Fault is one of the left-lateral strike-slip faults in the Bayan Hara Block. The Dari Fault starts at the eastern pass of the Kunlun Mountains, extends eastward through the south of Yalazela, Yeniugou and Keshoutan, the fault strike turns to NNE direction at Angcanggou, then turns to NE direction again at Moba town, Qinghai Province, and the fault ends near Nanmuda town, Sichuan Province, with a total length of more than 500km. The fault has been considered to be a late Quaternary active fault and the 1947 M73/4 Dari earthquake was produced by its middle segment. But studies on the late Quaternary activity of the Dari Fault are still weak. The previous research mainly focused on the investigation of the surface rupture and damages of the 1947 M73/4 Dari earthquake. However, there were different opinions about the scale of the M73/4 earthquake surface rupture zone. Dai Hua-guang(1983)thought that the surface rupture of the earthquake was about 150km long, but Qinghai Earthquake Agency(1984) believed that the length of surface rupture zone was only 58km. Based on interpretation of high-resolution images and field investigations, in this paper, we studied the late Quaternary activity of the Dari Fault and the surface rupture zone of the 1947 Dari earthquake. Late Quaternary activity in the central segment of the Dari Fault is particularly significant. A series of linear tectonic landforms, such as fault trough valley, fault scarps, fault springs and gully offsets, etc. are developed along the Dari Fault. And the surface rupture zone of the 1947 Dari earthquake is still relatively well preserved. We conducted a follow-up field investigation for the surface rupture zone of the 1947 Dari earthquake and found that the surface rupture related to the Dari earthquake starts at Longgen village in Moba town, and ends near the northwest of the Yilonggounao in Jianshe town, with a length of about 70km. The surface rupture is primarily characterized by scarps, compressional ridges, pull-apart basins, landslides, cleavage, and the coseismic offset is about 2~4m determined by a series of offset gullies. The surface rupture zone extends to the northwest of Yilonggounao and becomes ambiguous. It is mainly characterized by a series of linear fault springs along the surface rupture zone. Therefore, we suggest that the surface rupture zone of the 1947 Dari earthquake ends at the northwest of Yilonggounao. In summary, the central segment of the Dari Fault can be characterized by strong late Quaternary activity, and the surface rupture zone of the 1947 Dari earthquake is about 70km long. 相似文献