首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
祁连山活动断裂带中东段冷龙岭断裂滑动速率的精确厘定   总被引:14,自引:0,他引:14  
冷龙岭活动断裂是青藏高原东北缘祁连山断裂带的重要组成部分,位于祁连山断裂带中东段。根据野外考察结果认为,该断裂全新世以来活动强烈,主要表现为左旋走滑运动,并伴有正倾滑性质,断错地貌特征明显。通过高分辨率SPOT卫星数字影像和大比例尺航空照片处理确定断层的位置,利用断错地貌测图、热释光(TL)和碳十四(14C)测年方法,厘定了冷龙岭断裂的晚第四纪滑动速率,冷龙岭断裂晚更新世以来的平均水平滑动速率为(4.3±0.7)mm/a,全新世晚期以来的平均水平滑动速率为(3.9±0.36)mm/a。  相似文献   

2.
中旬-大具断裂南东段晚第四纪活动的地质地貌证据   总被引:1,自引:0,他引:1  
中甸-大具断裂南东段位于哈巴和玉龙雪山北麓,属于川西北次级块体西南边界,断裂总体走向310°~320°,是一条重要的边界断裂。了解该断裂的活动性质、活动时代和滑动速率等对分析川西北次级块体运动,研究该断裂与玉龙雪山东麓断裂的交切关系等问题具有重要意义。文中基于1︰5万活动断层地质填图,对断裂沿线地层地貌、陡坎地貌、地表破裂、典型断层剖面以及河流阶地等进行了详细的研究。研究表明:1)中甸-大具断裂南东段按几何结构、断错地貌表现、断裂活动性可分为马家村—大具次级段和大具—大东次级段。2)通过野外地质调查发现,马家村—大具次级段断错了全新世冲洪积扇,形成了地表破裂,为全新世活动段;而大具—大东次级段虽然也断错了晚更新—全新世地层,但其断错规模及滑动速率均较小,由此认为其全新世以来活动较弱。3)通过分析断裂沿线断层陡坎、水平位错及地表破裂等地质地貌问题,认为马家村—大具次级段的活动性质为右旋走滑兼正断,其晚更新世以来的垂直滑动速率为0. 4~0. 8mm/a,水平滑动速率为1. 5~2. 4mm/a;大具—大东次级段以右旋走滑为主、正断为辅,其晚更新世晚期以来的垂直滑动速率为0. 1mm/a。4)在大具盆地内发现的NW向地表破裂带的形成时代很年轻,不排除是1966年中甸6. 4级地震或1996年丽江7. 0级地震造成的地表破裂。  相似文献   

3.
通过对汗母坝-澜沧断裂晚第四纪地质、地貌实地调查与测量,并结合前人研究成果,讨论了该断裂晚第四纪最新构造活动特征。综合分析认为,汗母坝-澜沧断裂为一条以右旋走滑为主的全新世活动断裂,长约120 km,整体走向NNW。该断裂活动习性具有明显的分段特征,北段称为汗母坝断裂,是1988年耿马7.2级地震的发震断裂;南段称为澜沧断裂,是1988年澜沧7.6级地震的发震断裂之一。晚第四纪以来其新活动形成了丰富的断错地貌现象,如冲沟和山脊右旋位错、断层沟槽、断层垭口、断层陡坎、断陷凹坑等。根据断裂断错地貌特征的相应资料估计,该断裂晚第四纪右旋走滑速率约为(4.7±0.5) mm/a。  相似文献   

4.
罗云山山前断裂中段土门-贾朱村晚第四纪断错地貌特征   总被引:2,自引:0,他引:2  
罗云山山前断裂位于山西临汾盆地西侧,控制着盆地的西界。通过对该断裂1∶ 5万地质填图、对河流冲沟阶地及山前断错地貌的调查,介绍了罗云山山前断裂中段土门-贾朱村晚第四纪断错地貌特征。罗云山山前发育D1、D2、D3 等3 级洪积扇,罗云山山前断裂上升盘冲沟发育T1 ~ T5 等5 级阶地。D1 洪积扇与T1、T2 阶地形成于全新世早中期;D2 洪积扇与T3 阶地形成于晚更新世中晚期;D3 洪积扇与T4、T5 阶地形成于中更新世中晚期。罗云山山前断裂中段不同部位断错地貌特征差异较大,D1 洪积扇的断错在席坊沟一带断距约2. 9m;在金殿镇峪口村南西山前断错约3m。D2 洪积扇的断错在土门镇南西堡子村约2. 5m;在杨家庄村西山前断错约4m;在景村西山前断错约6m;在襄陵镇浪泉沟南西侧山前断错约7. 7m。罗云山山前断裂中段山前断错地貌明显,其最新活动时代为全新世。其中,土门段最新活动时代为全新世早期,龙祠段最新活动时代为全新世中晚期。罗云山山前断裂中段晚更新世中晚期以来活动速率为0. 18~ 0. 54mm / a,由北向南活动呈增强趋势;全新世早中期以来活动速率为0. 4 ~ 0. 9mm / a,断裂活动主要集中于席坊沟-峪口一带。罗云山山前断裂中段从晚更新世中晚期到全新世活动速率有增大的趋势,这与该断裂上升盘冲沟阶地从晚更新世中晚期到全新世抬升速率有增大的趋势以及临汾盆地从晚更新世晚期到全新世沉降速率也有增大的趋势具有较好的一致性。  相似文献   

5.
龙陵-瑞丽断裂(南支)北段晚第四纪活动性特征   总被引:5,自引:0,他引:5       下载免费PDF全文
遥感影像解译和野外地质地貌调查表明,龙陵-瑞丽断裂(南支)北段是以左旋走滑为主兼张性正断的区域性活动断裂。根据一些断错地貌点的大比例尺填图、实地测量及其年代学分析,确定了该断裂为全新世活动断裂,断裂晚更新世以来的平均水平滑动速率为2.2mm/a,平均垂直滑动速率为0.6mm/a;全新世以来的平均水平滑动速率为1.8~3.0mm/a,平均垂直滑动速率为0.5mm/a。断裂晚更新世以来的滑动速率在不同的时间尺度上变化不大,反映了该断裂晚更新世以来的活动强度比较平稳  相似文献   

6.
西秦岭北缘断裂带是青藏高原东缘一条大型左旋走滑活动断裂带和历史强震带。前人对该断裂漳县以西段曾开展过大量研究工作,获得其最新构造活动的地质地貌证据,而中段(武山—天水段)和东段(天水—宝鸡段)最新活动时代一直存在分歧。基于高分辨率卫星影像解译、地质地貌调查与综合分析、探槽开挖和~(14)C测年等方法,对西秦岭北缘断裂带武山—天水段进行详细研究,结果表明:该段断裂晚第四纪以来活动显著,地貌上主要表现为断层垭口、断层沟槽、山脊与水系及阶地同步左旋位错、断层陡坎等;多个探槽剖面及测年结果显示其最新构造活动断错了全新世地层,为该段断裂全新世活动和大震危险性分析提供了新的证据。  相似文献   

7.
基于华山山前断裂1︰5万活动断层填图成果,对断裂沿线地层地貌、断层三角面、河流阶地、陡坎地貌以及典型断错剖面等进行了详细的研究。研究表明:1)华山山前断裂按几何结构、断错地貌表现分西段(蓝田—华县段)、中段(华县—华阴段)及东段(华阴—灵宝段)3段;2)西段及东段断裂错断了T_2阶地及马兰黄土,T_1阶地跨断裂连续,测年结果表明,T_2阶地形成于晚更新世中期,T_1阶地形成于全新世早期,由此得出西段及东段断裂在晚更新世有过活动,全新世以来活动弱或不活动;3)中段断错地貌显著,河谷两侧发育Ⅲ级阶地,跨断裂阶地均被错断,测年结果表明:T_1阶地形成于2~3kaBP,T_2阶地形成于6~7kaBP,T_3阶地形成于60~70kaBP,结合阶地陡坎高度,得出不同时段的平均垂直滑动速率:T_3—T_2时期0.4mm/a;T_2—T_1时期1.1mm/a;T_1以来1.6mm/a;4)中段在晚更新世晚期以来发生过多次活动,在石堤峪、沟峪等地见漫滩陡坎,结合文化层及炭样年龄,可知漫滩形成于距今400~600a,对比历史地震资料,漫滩陡坎应为华县1556年地震的遗迹;5)结合前人研究认为,公元1556年华县81/2级地震的发震构造为华山山前断裂及渭南塬前断裂,其它断裂是否参与有待进一步研究。  相似文献   

8.
天全-荥经断裂是青藏高原东南缘的1条晚第四纪且活动资料较少的断裂,在2008年汶川M 8.0地震之后,龙门山断裂带西南端未来的地震危险性受到关注。对天全-荥经断裂晚第四纪活动特征的获取有助于理解该区地震危险性的评价。通过遥感影像解译,结合野外调查和断错地貌测量,分析了天全-荥经断裂在荥经下坝村至桂花村切过荥经河河谷晚第四纪地貌区的活动证据。断裂沿线形成冲积扇断错、阶地坎断错和断坎等地貌,并沿断裂发育滑坡。晚第四纪以来断裂以左旋走滑活动为主,其中T2/T2'阶地坎被左旋断错22—24m。利用荥经河阶地与青衣江河流阶地对比,认为该断裂20—40ka以来左旋走滑速率为0.6—1.1mm/a。仍需要从古地震等方面开展工作,来进一步确定天全-荥经断裂的地震危险性。  相似文献   

9.
阿拉善地块南缘地处青藏高原东北缘地壳扩展前锋带的北侧,对该地区活动断裂晚第四纪的运动性质、滑动速率等开展研究,有助于理解阿拉善地块的晚第四纪构造变形特征及其对青藏高原向N扩展的响应。文中结合遥感影像解译与野外地质地貌考察,对阿拉善地块南缘的北大山断裂进行了分段和活动性研究。结果表明,北大山断裂左旋走滑断错晚第四纪洪积扇和阶地等地貌,形成显著的位错阶地坎、冲沟以及断层陡坎。通过对断错地貌线等标志的测量、复原、统计分析等,发现断裂的地貌位移值分布于3~20m,发育新鲜断层自由面的断层陡坎和左旋错动的纹沟指示了断层的最新一次活动。基于同期洪积扇年龄估算得到北大山断裂晚更新世以来的左旋滑动速率为0.3~0.6mm/a。北大山断裂的运动学特征与区域NE向应力场一致,可能受到了青藏高原NE向扩展的影响。  相似文献   

10.
文中从几何结构特征、断裂长期滑动速率和古地震复发特征3个方面对阿万仓断裂进行了研究。详细的遥感解译和野外调查结果表明:1)阿万仓断裂作为东昆仑断裂带东段(玛沁—玛曲段)的分支断裂,和东昆仑断裂一样也是1条全新世活动断裂,性质为左旋走滑兼逆断,总长约200km。西北段由2条总体走向310°,相距约16km近平行的次级断层组成,向SE方向合为1条断裂。2)在阿万仓断裂上发现大约15km长的古地震地表破裂带,表现为断层陡坎、断塞塘、地裂缝、断层沟槽等典型断错微地貌现象。3)经航、卫片解译,野外现场调查,断错地貌测量和样品测试,得到该断裂晚第四纪以来的平均左旋水平滑动速率为3mm/a,垂直滑动速率约0.07mm/a。4)通过对断错最新地貌面的测年和探槽剖面分析,认为阿万仓断裂带存在4次古地震事件,属原地复发型,最新1次事件是在(850±30)a BP以后发生的。5)阿万仓断裂左旋滑动速率与东昆仑断裂带玛沁—玛曲段递减的滑动速率量值相当,它的存在和发现可以很好地解释东昆仑断裂带东段(玛沁—玛曲段)滑动速率递减的特征。东昆仑活动断裂带中东段滑动速率逐渐递减,与东昆仑活动断裂带中东段帚状散开的几何结构有关,其中的阿万仓断裂是东昆仑断裂带东延过程中的重要分支断裂,吸收了东昆仑断裂带东延的应变分配。  相似文献   

11.
利用14C、热释光(TL)样品年代及扩散方程计算结果,结合区域黄土剖面中古土壤年龄,对毛毛山地区晚第四纪各级地貌年龄进行了对比研究。根据毛毛山活动断裂水平位移和垂直位移分布明显的分组特征,求得毛毛山断裂带不同段落不同时段的平均滑动速率。大约自中更新世晚期以来,毛毛山断裂走滑段的平均水平滑动速率为2.3~3.9mm/a,垂直滑动速率为0.07~0.19mm/a;天祝盆地倾滑段垂直滑动速率为0.11~0.86mm/a。沿断裂带滑动速率具明显的非均匀性特点,表现为自东向西水平位移具累积滑动亏损特征,垂直位移则具补偿性  相似文献   

12.
滑动速率是研究断裂运动学特征、地震活动性和区域应变分配的重要参数和依据。前人关于甘孜-玉树断裂带滑动速率的研究结果存在较大差异,因此,其晚第四纪滑动速率有待进一步调查研究。本文基于卫星影像解译和野外实地考察,对甘孜-玉树断裂带西段(玉树断裂)上典型断错地貌点进行测量分析,得到玉树断裂晚第四纪走滑速率为6.6±0.1-7.4±1.2mm/a。通过与前人对甘孜-玉树断裂带东段(甘孜断裂)滑动速率的研究结果进行对比,发现甘孜-玉树断裂带东、西段滑动速率不一致,其原因是甘孜断裂的左旋滑移在向西传递的过程中,一部分应变被分配到了巴塘盆地南缘断裂上。巴塘盆地南缘断裂的存在很好地解释了玉树断裂的走滑速率比甘孜断裂偏低的原因。但是,从区域变形来看,巴塘盆地南缘断裂分配的滑动速率恰好说明了甘孜-玉树断裂带东、西段及鲜水河断裂带的水平构造变形是协调一致的。  相似文献   

13.
甘孜-玉树断裂带东南段晚第四纪活动性研究   总被引:3,自引:1,他引:2       下载免费PDF全文
以甘孜-玉树断裂带东南段的地质地貌为研究对象,在遥感解译的基础上,通过对典型地区的详细野外调查和探槽研究对该段晚第四纪活动性进行研究。在断裂沿线的生康乡、仁果乡、错阿乡、日阿乡进行了断错地貌分析和晚第四纪滑动速率计算, 生康区的水平滑动速率为(7.6±0.5)mm/a, 垂直滑动速率为(1.1±0.1)mm/a; 仁果区的水平滑动速率为(8.0±0.3)mm/a,垂直滑动速率为(1.1±0.1)mm/a; 错阿区的水平滑动速率为(10.3±0.4)mm/a; 日阿区的水平滑动速率为(10.8±0.8)mm/a, 垂直滑动速率为(1.1±0.1)mm/a。在仁果乡和错阿乡进行了探槽研究,两处探槽都揭示了多次古地震事件,虽然揭露的断层构造样式有所不同,但总体上都是以走滑为主兼有一定的逆冲分量。综合古地震事件和滑动速率分析表明,甘孜-玉树断裂带东南段晚第四纪尤其是全新世以来活动剧烈。  相似文献   

14.
The I ingwu fault is in the eastern boundary of the southern section of Yinchuan graben. It hasa close relation to seismicity in the Lingwu-Wuzhong region.Few researches have been done.In this Paper,on the basis of tee data obtained from field investigation,the activity features inLate Quaternary have been discussed.The vertical displacement and its slip rate have been alsoestimated.The fault is 48km in length,being divided into 3 segments according to geologicaland topographical characteristics.The last rupture along its northern and middle segments wasoccurred in late of Late Pleistocene or early Holocene while that along the southern segmentwas occurred in midle Holocene.The vertical slip rate is estimated as 0.23~025mm/a sinceabout 66ka B.P.based on the vertical displacements of terracesⅠ,Ⅱ and Ⅲ and their ages.  相似文献   

15.
The Dengdengshan and Chijiaciwo faults situate in the northeast flank of Kuantanshan uplift at the eastern terminal of Altyn Tagh fault zone, striking northwest as a whole and extending 19 kilometers and 6.5 kilometers for the Dengdengshan and Chijiaciwo Fault, respectively. Based on satellite image interpretation, trenching, faulted geomorphology surveying and samples dating etc., we researched the new active characteristics of the faults. Three-levels of geomorphic surfaces, i.e. the erosion rock platform, terrace I and terrace Ⅱ, could be found in the northeast side of Kuantanshan Mountain. The Dengdengshan Fault dislocated all geomorphic surfaces except terrace I, and the general height of scarp is about 1.5 meters, with the maximum reaching 2.6 meters. Three paleoseismic events are determined since late Pleistocene through trenching, and the total displacement of three events is about 2.7 meters, the average vertical dislocation of each event changed from 0.5 to 1.2 meters. By collecting age samples and dating, the event Ⅰ occurred about 5ka BP, event Ⅱ occurred about 20ka BP, and event Ⅲ occurred about 35ka BP. The recurrence interval is about 15ka BP; and the vertical slip rate since the late Pleistocene is about 0.04mm/a. The Chijiaciwo Fault, however, dislocated all three geomorphic surfaces, and the general scarp height is about 2.0 meters with the maximum up to 4.0 meters. Three paleoseismic events are determined since late Pleistocene through trenching, and the total displacement of three events is about 3.25 meters, the average vertical dislocation of each event changed from 0.75 to 1.5 meters, and the vertical slip rate since the late Pleistocene is about 0.06mm/a. Although the age constraint of paleoearthquakes on Chijiaciwo Fault is not as good as that of Dengdengshan Fault, the latest event on Chijiaciwo Fault is later than Dengdengshan Fault's. Furthermore, we infer that the recurrence interval of Chijiaciwo Fault is 15ka BP, which is close to that of Dengdengshan Fault. The latest event on Chijiaciwo Fault is later than the Dengdengshan Fault's, and the vertical displacement and the slip rate of a single event in late Quaternary are both larger than that of Dengdengshan Fault. Additionally, a 5-kilometer-long discontinuity segment exists between these two faults and is covered by Quaternary alluvial sand gravel. All these indicate that the activity of the Chijiaciwo Fault and Dengdengshan Fault has obvious segmentation feature. The size of Chijiaciwo Fault and Dengdengshan Fault are small, and the vertical slip rate of 0.04~0.06mm/a is far smaller than that of Qilianshan Fault and the NW-striking faults in Jiuxi Basin. All these indeicate that the tectonic deformation of this region is mainly concentrated on Hexi Corrider and the interior of Tibet Plateau, while the activties of Chijiaciwo and Dengdengshan faults are characterized by slow slip rate, long recurrence interval(more than 10ka)and slow tectonic deformation.  相似文献   

16.
大盈江断裂晚更新世以来活动的地质证据   总被引:8,自引:1,他引:7       下载免费PDF全文
大盈江断裂新构造活动特征明显,断层三角面、线性山脊、断层槽地等断层地貌发育,卫星影像上线性特征清晰,断裂对梁河、盈江盆地、桑岗、西帕河等第四纪盆地具有明显的控制作用.根据近年来境内外野外调查结果,大坪子、丙辉村、老新寨、热水塘、广云村等多处断层露头显示错断了晚更新世或全新世地层.丙辉村被错地层年龄为(56.56±4.8...  相似文献   

17.
The Shanxi Graben System is one of the intracontinental graben systems developed around the Ordos Block in North China since the Cenozoic, and it provides a unique natural laboratory for studying the long-term tectonic history of active intracontinental normal faults in an extensional environment. Comparing with the dense strong earthquakes in its central part, no strong earthquakes with magnitudes over 7 have been recorded historically in the Jin-Ji-Meng Basin-and-Range Province of the northern Shanxi Graben System. However, this area is located at the conjunction area of several active-tectonic blocks(e.g. the Ordos, Yan Shan and North China Plain blocks), thus it has the tectonic conditions for strong earthquakes. Studying the active tectonics in the northern Shanxi Graben System will thus be of great significance to the seismic hazard assessment. Based on high-resolution remote sensing image interpretations and field investigations, combined with the UAV photogrammetry and OSL dating, we studied the late Quaternary activity and slip rate of the relatively poorly-researched Yanggao-Tianzhen Fault(YTF)in the Jin-Ji-Meng Basin-and-Range Province and got the followings: 1)The YTF extends for more than 75km from Dashagou, Fengzhen, Inner Mongolia in the west to Yiqingpo, Tianzhen, Shanxi Province in the east. In most cases, the YTF lies in the contact zone between the bedrock mountain and the sediments in the basin, but the fault grows into the basin where the fault geometry is irregular. At the vicinity of the Erdun Village, Shijiudun Village, and Yulinkou Village, the faults are not only distributed at the basin-mountain boundary, we have also found evidence of late Quaternary fault activity in the alluvial fans that is far away from the basin-mountain boundary. The overall strike of the fault is N78°E, but the strike gradually changes from ENE to NE, then to NWW from the west to the east, with dips ranging from 30° to 80°. 2)Based on field surveys of tectonic landforms and analysis of fault kinematics in outcrops, we have found that the sense of motion of the YTF changes along its strikes: the NEE and NE-striking segments are mainly normal dip-slip faults, while the left-laterally displaced gullies on the NWW segment and the occurrence characteristics of striations in the fault outcrop indicate that the NWW-striking segment is normal fault with minor sinistral strike-slip component. The sense of motion of the YTF determined by geologic and geomorphic evidences is consistent with the relationship between the regional NNW-SSE extension regime and the fault geometry. 3)By measuring and dating the displaced geologic markers and geomorphic surfaces, such as terraces and alluvial fans at three sites along the western segment of the YTF, we estimated that the fault slip rates are 0.12~0.20mm/a over the late Pleistocene. In order to compare the slip rate determined by geological method with extension rate constrained by geodetic measurement, the vertical slip rates were converted into horizontal slip rate using the dip angles of the fault planes measured in the field. At Zhuanlou Village, the T2 terrace was vertically displaced for(2.5±0.4)m, the abandonment age of the T2 was constrained to be(12.5±1.6)ka, so we determined a vertical slip rate of(0.2±0.04)mm/a using the deformed T2 terrace and its OSL age. For a 50°dipping fault, it corresponds to extension rate of(0.17±0.03)mm/a. At Pingshan Village, the vertical displacement of the late Pleistocene alluvial fan is measured to be(5.38±0.83)m, the abandonment age of the alluvial fan is(29.7±2.5)ka, thus we estimated the vertical slip rate of the YTF to(0.18±0.02)mm/a. For a 65° dipping fault, it corresponds to an extension rate of(0.09±0.01)mm/a. Ultimately, the corresponding extensional rates were determined to be between 0.09mm/a and 0.17mm/a. Geological and geodetic researches have shown that the northern Shanxi Graben System are extending in NNW-SSE direction with slip rates of 1~2mm/a. Our data suggests that the YTF accounts for about 10% of the crustal extension rate in the northern Shanxi Graben System.  相似文献   

18.
使用全站仪实测了天山南麓北轮台逆断裂库尔楚段阿克艾肯-喀腊萨喀腊阿塔木冲洪积扇断层崖地形地貌,采用^10Be测年方法测定了该冲洪积扇的形成年龄,得到该断裂段垂直位移滑动速率为0.48mm/a、0.85-1.0mm/a和1.52mm/a,并对该断裂段的水平缩短速率和天山第四纪水平缩短量进行了讨论。  相似文献   

19.
INTRODUCTIONGeological investigations since the1970s have shown that the sub_longitudinal Jinshajiang andHonghe(Red River)fault zones constitutethe western boundary of“Rhombic Sichuan_Yunnan Block”onthe Sichuan_Tibet border and display mainly dextral sh…  相似文献   

20.
The northern piedmont fault of Wutai Mountain is located at the north of the Shanxi Graben system,which is the dominating fault of the south boundary of the Fanshi-Daixian depression. This paper discusses the fault activity and paleoearthquakes around the Nanyukou segment of the northern piedmont fault of Wutai Mountain during the late Quaternary through field investigation along the fault,measuring geomorphic deformation and excavating trenches at some important sites. From Nanyukou to the southwest of Shanhui,we find obviously dislocated alluvial fans,with strong neotectonic movement at these sites. Since nearly 20ka,the vertical average slip rate is 1. 55mm /a to 2. 0mm /a. However,since nearly 6ka,it has reached as high as 2. 3mm /a,which is twice that on other segments. 2 trenches were excavated around Nanyukou with 6 events discovered. The referenced ages of the events are before 7600a,6700a ~ 7600a,5321a ~ 5575a,4400a ~ 5400a,4200a ~ 4400a and after 1600a B. P. with approximate recurrence interval 1400a. The latest event is likely to be the earthquake occurring at 512 A. D. ,so it is necessary to do further work to verify this in the future.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号