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1.
对合肥盆地东缘基岩区的NW向断层剖面进行了观察和年代样品测试,并跨其中1条断层布设了浅层地震勘探测线;结合本区第四系厚度和沉积特征,对浅震测线时间剖面进行了地质解释。根据调查所揭示的剖面特征、断层泥ESR测年数据、浅层地震勘探结果及本区的中强地震活动构造背景,认为这组NW向断裂中更新世有过活动;合肥盆地东缘NW向横向断裂的第四纪活动情况与断裂所在地区的新构造环境有关,尽管断层泥测年结果表明断裂在中更新世有过活动,但其活动强度不大。  相似文献   

2.
为确定渭河断裂中部隐伏段的位置,在咸阳窑店布设了浅层地震勘探测线,在浅层地震勘探资料对断层解译的基础上,进一步开展了窑店和陈家沟钻孔联合剖面勘探工作,详细查明了渭河断裂的精确位置和组合特征,结合钻孔土样光释光(OSL)年龄测试和区域地层资料,深入研究了渭河断裂带最新活动年代和滑动速率等特征。  相似文献   

3.
前人对于郯庐断裂带安徽段出露部分的活动性开展了不同程度的研究,并获得了丰富的成果,而对于隐伏于合肥盆地中的段,其活动性如何,甚至断裂是否存在一直未能取得明确认识。文中利用浅层地震勘探及钻探联合地质剖面探测方法,对隐伏于合肥盆地中的郯庐断裂带西分支断层——乌云山-合肥断裂开展了详细的探测研究工作,在合肥城区由北向南跨断裂布设了4条浅层地震勘探测线和2排联合钻孔剖面,采用~(14)C、OSL和ESR 3种测年手段共获得了34个钻孔地层剖面样品的年龄数据,结果显示乌云山-合肥断裂错动的最新地层为中更新统青灰色黏土层,断层活动表现为逆断性质,最大垂直错距达2. 4m,最新活动时代为中更新世晚期,上断点最浅埋深达17m。文中研究证实了郯庐断裂带穿切合肥盆地,且第四纪以来仍有活动,所得成果充实了对郯庐断裂带安徽段总体活动的认识。  相似文献   

4.
在地质调查与盆地区浅层人工地震初步勘探基础上,在西秦岭北缘断裂带漳县盆地隐伏段的盆地内布设了3条浅层人工地震详勘测线,用于精确定位该断层的空间展布,判定其浅地表活动特征。在此基础上,用钻孔联合剖面方法对人工地震探测结果进行验证,同时确定了各地震测线处断层上断点的位置和埋深,通过钻孔揭露断层错断地层的特点,认为西秦岭北缘断裂漳县盆地隐伏段错断全新统,指示该断层全新世以来活动性较强。  相似文献   

5.
昌平-丰南断裂构造浅层地震勘探新证据   总被引:1,自引:1,他引:0       下载免费PDF全文
昌平-丰南断裂是根据卫星遥感图像解译发现的一条隐伏活动断层,是NWW向张家口-蓬莱断裂带中规模最大的断裂,为进一步调查确认断裂的存在、空间位置、性质和断裂构造特征,并重新厘定其活动性,在卫星遥感影像解译断裂大体空间位置的基础上,布设了2条浅层地震勘探测线,对昌平-丰南断裂进行了高分辨率地震勘探,获得了测线控制范围内地下结构和断裂构造的清晰成像。结果表明,昌平-丰南断是一条倾向S、走向NWW的走滑正断层,浅层地震剖面揭示断层上断点埋深80~100 m,断错了上更新统底界,结合测线附近钻孔资料推测其最新活动时代为晚更新世。  相似文献   

6.
通过野外地质调查、浅层地震勘探和钻孔联合剖面探测等方法,对废黄河断裂的第四纪活动性进行了研究。浅层地震勘探结果表明,废黄河断裂由南北两条主干断裂组成,南支断裂倾向NE,北支断裂倾向SW,总体为一地堑形式,断裂宽度为1~2km。在地震剖面上,废黄河断裂的各个断点都是以断错基岩面为特征,并未断错第四系内部层位。钻孔联合剖面探测结果显示,废黄河断裂断错了中更新统层位,但未断错其顶面。在凤山一带发现1条废黄河断裂的次级断层出露,结合断层泥胶结程度、测年结果和地貌特征等判断,该断层最新活动为中更新世中期。综合以上研究工作成果,判断废黄河断裂早期为左旋活动,第四纪以来表现为张性活动,其最新活动时代为中更新世中期。受构造背景的控制,徐州地区发育的NW向断裂明显较相邻的鲁西南地区的NW向断裂活动性弱。  相似文献   

7.
戴王强  韩恒悦  李晓妮  任隽  冯希杰 《地震》2007,27(4):129-136
通过临潼-长安断裂带少陵塬段小鲍陂一带断层陡坎和断层剖面的地质调查, 并结合黄土地层光释光(OSL)年龄测试和钻孔探测, 研究了该段落晚第四纪以来的地貌标志、 活动方式和幅度以及平均滑移速率。 该断裂断面明显错断了古土壤(S1)底界, 并且断层上断面以裂缝形式延伸至弱古土壤(L1s)地层中, 根据光释光(OSL)测年结果该断裂至少在晚更新世中晚期以来仍有活动, 以断层两侧晚更新世底界S1地层稳定的趋势面为标志, 错距达5 m多。  相似文献   

8.
郯庐断裂带合肥段五河—合肥断裂构造特征   总被引:3,自引:0,他引:3       下载免费PDF全文
五河—合肥断裂是郯庐断裂带的西边界断裂,该断裂穿过合肥市城区,是1条规模较大、切割较深的隐伏活动断裂.为了研究该断裂的浅部结构特征、空间展布以及断裂活动性,我们利用2015年在合肥盆地完成的深地震反射剖面数据,采用初至波层析成像方法得到了郯庐断裂带合肥段的浅层P波速度结构和构造形态;考虑到仅根据速度结构剖面还难以确定断裂的准确位置、断层上断点埋深、断层的近地表构造组合样式等特征,研究中跨五河—合肥断裂还完成了2条高分辨率的浅层地震反射剖面.研究结果表明:郯庐断裂带合肥段是一个由多条主干断裂构成的复杂构造带,近地表速度结构表现为凹隆相间的构造特征,且沉积盖层厚度明显受到郯庐断裂带分支断裂的影响和控制.五河—合肥断裂在P波速度结构剖面表现为高速和低速区的分界,对断裂两侧的地层沉积具有重要的控制作用,该断裂向下错断了盆地基底,向上错断了埋深21~35 m的中更新统下部地层,其最新活动时代为中更新世早期.研究结果不仅为进一步认识五河—合肥断裂浅部构造形态提供了地震学依据,还可为该区断裂两侧的城镇规划和建设中避让活动断层提供基础资料.  相似文献   

9.
新乡-商丘断裂是南华北盆地与渤海湾盆地、鲁西隆起的分界断裂,是一条长期活动的区域性深大断裂。浅层地震勘探与跨断层钻孔联合剖面探测工作已证实该断裂延津至封丘段的最新活动时代为晚更新世,本文通过对典型地震勘探剖面和钻探资料综合分析认为:新乡-商丘断裂延津至封丘段断裂结构复杂,新近纪以来构造样式在不同构造部位有显著差异。延津段在地震勘探剖面上浅部显示为负花状构造;封丘段变化较大,东部在剖面上为多组阶状正断层组合,形成了由断层带控制的构造背斜,平面上表现为NW向排列、走向NNE雁列状断层组合;西部结构单一,自东向西断裂控制的浅部地层变形范围增大,断层带逐步变宽。根据新乡-商丘断裂延津至封丘段剖面上的构造样式与平面上的组合模式,表明该段断裂最新活动具有走滑运动性质。  相似文献   

10.
河西务断裂活动性的综合探测研究   总被引:2,自引:1,他引:1  
河西务断裂为河西务构造带的东缘断裂,总体走向北东,倾向南东,向北延伸与廊固凹陷内的横向断层(桐柏断裂)小角度相接,向南延伸与牛东断裂相接,为廊固凹陷与武清凹陷的分界断裂,隐伏于冀中凹陷覆盖层之下。本文通过浅层地震勘探和钻孔联合剖面探测,结合年代样品测试,对河西务断裂的活动性和滑动速率进行了综合研究,揭示断裂上断点埋深约150m或以浅,第四系底界面的垂直错距为20—45m,断裂的最新活动时代为晚更新世早期,晚更新世以来的平均垂直滑动速率为0.03mm/a,中更新世晚期以来的平均垂直滑动速率为0.11mm/a。  相似文献   

11.
Because of the frequent seismic activity in Songyuan in recent years, the modes of tectonic movement in this area since the Quaternary have attracted increasing consideration. This paper selects the Gudian Fault which locates between the southeast uplift and central depression of Songliao Basin as the research object. We discussed the Quaternary structural characteristics of the Gudian Fault using growth strata. Using the data of deep seismic reflection prospecting for oil, we determined the location, geometry and kinematics characteristics of the Gudian Fault. And using the shallow seismic reflection prospecting data, the combined drilling exploration data and TL data, we determined precisely the inversion tectonics feature of the fault since late Cenozoic. Based on the above data, we believe that the Gudian Fault is dominated mainly by thrust-folding since Quaternary. A set of growth strata is recognized by shallow seismic reflection exploration data. According to the overlap of growth strata and the relationship between deposition rate and uplift rate, we confirm that the uplift rate of Gudian Fault in the early of Early Pleistocene is less than 0.15mm/a. And according to the offlap of growth strata and the relationship between deposition rate and uplift rate, the uplift rate of the Gudian Fault is more than 0.091mm/a in the late of Early Pleistocene and more than 0.052mm/a in middle Pleistocene. According to the chronological data, it is determined that the uplift rate of the Gudian Fault is 0.046mm/y since 205ka.  相似文献   

12.
Existing achievements about Baotou Fault demonstrate it as a buried eastern boundary of the Baiyanhua Basin in Hetao active fault subsidence zone,striking NE.More data is needed to assess its activity.Located in the relay ramp between Wulashan Fault and Daqingshan Fault,Baotou Fault's activity is of great importance to discuss the linkage mode and the response to the earthquake of the adjacent fault.Also it is necessary to the knowledge of the characteristic of the seismic tectonic in local area.Recently it is prevalent to combine shallow seismic profile and composite drilling section to study the activity of the buried fault.Shallow seismic profile indicates that Baotou Fault is a normal fault,inclining to NW.The displacement of the Tg at 75m underground is 25m.Composite drilling section indicates that it is a growth fault,the up-break point of which is 45.6m underground and ends in brownish red clay strata of early Pleistocene.In comparison,the upper Late Pleistocene strata are out of the influences of the tectonic subsidence zone.Baotou Fault's activity is limited to the early Pleistocene.  相似文献   

13.
应用浅层地震勘探法对宁夏吴忠地区北部的浅部地壳结构和隐伏活动断裂进行研究。结果表明,该区存在2条隐伏断裂,分别为银川主断层南段和新华桥断层。推测银川主断层南段为近SN走向的W倾正断层,断层下盘地层界面一般呈近水平状展布,而在断层上盘,T_Q及其以下的地层界面向断面方向倾伏并显示出逆牵引现象,断层向上错断了第四系内部。钻孔联合地质剖面及浅层地震探测结果共同揭示新华桥断层为一条走向NE,倾向SW的正断层,深、浅地震测线控制的新华桥断层延伸长度9 km左右,向上错断了第四系内部的T_(02)界面。  相似文献   

14.
Pangusi-Xinxiang Fault is a great-scale, deep-incising buried active fault in the southern margin of the Taihang Mountains. In order to find out the location, characteristics, structure and activities of Pangusi-Xinxiang Fault, shallow reflection profiles with six lines crossing the buried faults were carried out. In this paper, based on the high-resolution seismic data acquisition technology and high-precision processing technology, we obtained clear images of underground structures. The results show that Pangusi-Xinxiang Fault is a near EW-trending Quaternary active fault and its structural features are different in different segment. The middle part of the fault behaves as a south-dipping normal fault and controls the north boundary of Jiyuan sag; The eastern part of the fault is a north-dipping normal fault and a dividing line of Wuzhi uplift and Xiuwu sag. The shallow seismic profiles reveal that the up-breakpoint of the Pangusi-Xinxiang Fault is at depth of 60~70m, which offsets the lower strata of upper Pleistocene. We infer that the activity time of this fault is in the lower strata of late Pleistocene. In this study, not only the location and characteristics of Pangusi-Xinxiang Fault are determined, but also the reliable geological and seismological evidences for the fault activity estimation are provided.  相似文献   

15.
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   

16.
青岛沧口断裂的地质构造特征与第四纪活动性研究   总被引:1,自引:1,他引:0  
本文根据青岛市活断层探测与地震危险性评价项目初查阶段第四纪地层分析、遥感影像解译、地球化学探测、地质地貌调查与探槽开挖、浅层地震勘探与钻孔探测、地质年代测定等获得的丰富的第一手资料,对青岛沧口断裂的地质构造特征和第四纪活动性进行了详细分析与综合研究,结果表明:沧口断裂经历多期构造变动,是本区的重要断裂之一,它由多支断层组成,控制了中生代的火山活动、盆地沉积和岩浆侵入以及晚第四纪的盆地沉积、山体隆升和水系发育;第四纪以来,沧口断裂的主要活动发生于中更新世晚期至晚更新世早期,表现出中高角度向南东倾的逆冲活动特点,错断了上更新统底面1—6m,而最新活动时代为晚更新世中期,以走滑活动为主,垂直错距0.2—1.1m。  相似文献   

17.
Running across the urban areas of Changzhou, Wuxi and Suzhou, the NW-trending Su-Xi-Chang Fault is an important buried fault in Yangtze River Delta. In the respect of structural geomorphology, hilly landform is developed along the southwest side of the Su-Xi-Chang Fault, and a series of lakes and relatively low-lying depressions are developed on its northeast side, which is an important landform and neotectonic boundary line. The fault controlled the Jurassic and Cretaceous stratigraphic sedimentary and Cenozoic volcanic activities, and also has obvious control effects on the modern geomorphology and Quaternary stratigraphic distribution. Su-Xi-Chang Fault is one of the target faults of the project "Urban active fault exploration and seismic risk assessment in Changzhou City" and "Urban active fault exploration and seismic risk assessment in Suzhou City". Hidden in the ground with thick cover layer, few researches have been done on this fault in the past. The study on the activity characteristics and the latest activity era of the Su-Xi-Chang Fault is of great significance for the prevention and reduction of earthquake disaster losses caused by the destructive earthquakes to the cities of Changzhou, Wuxi and Suzhou. Based on shallow seismic exploration and drilling joint profiling method, Quaternary activities and distribution characteristics of the Su-Xi-Chang Fault are analyzed systematically. Shallow seismic exploration results show that the south branch of the Su-Xi-Chang Fault in Suzhou area is dominated by normal faulting, dipping to the north-east, with a dip angle of about 60° and a displacement of 3~5m on the bedrock surface. The north branch of the Su-Xi-Chang Fault in Changzhou area is dominated by normal faulting, dipping to the south, with a dip angle of about 55°~70° and a displacement of 4~12m on the bedrock surface. All breakpoints of Su-Xi-Chang Fault on the seismic exploration profiles show that only the bedrock surface was dislocated, not the interior strata of the Quaternary. On the drilling joint profile in the Dongqiao site of Suzhou, the latest activity of the south branch of Su-Xi-Chang Fault is manifested as reverse faulting, with maximum displacement of 2.9m in the upper part of Lower Pleistocene, and the Middle Pleistocene has not been dislocated by the fault. The fault acts as normal fault in the Pre-Quaternary strata, with a displacement of 3.7m in the Neogene stratum. On the drilling joint profile in the Chaoyang Road site of Changzhou, the latest activity of the north branch of Su-Xi-Chang Fault is manifested as reverse faulting too, with maximum displacement of 2.8m in the bottom layer of the Middle Pleistocene. The fault acts as normal fault in the Pre-Quaternary strata, with a displacement of 10.2m in the bedrock surface. Combining the above results, we conclude that the latest activity era of Su-Xi-Chang Fault is early Middle Pleistocene. The Su-Xi-Chang Fault was dominated by the sinistral normal faulting in the pre-Quaternary period, and turned into sinistral reverse faulting after the early Pleistocene, with displacement of about 3m in the Quaternary strata. The maximum magnitude of potential earthquake on the Su-Xi-Chang Fault is estimated to be 6.0.  相似文献   

18.
The Daxing Fault is an important buried fault in the Beijing sub-plain, which is also the boundary fault of the structural unit between Langgu sub-sag and Daxing sub-uplift. So far, there is a lack of data on the shallow tectonic features of the Daxing Fault, especially for the key structural part of its northern section where it joins with the Xiadian Fault. In this paper, the fine stratigraphic classifications and shallow tectonic features of the northern section in the main Daxing Fault are explored by using three NW-trending shallow seismic reflection profiles. These profiles pass through the Daxing earthquake(M6¾)area in 1057AD and the northern section of the main Daxing Fault. The results show that seven strong reflection layers(T01—T03, TQ and T11—T13)are recognized in the strata of Neogene and Quaternary beneath the investigated area. The largest depth of strong reflection layer(T13)is about 550~850ms, which is interpreted as an important surface of unconformity between Neogene and Paleogene or basement rock. The remaining reflection layers, such as T01 and TQ, are interpreted as internal interfaces in Neogene to Quaternary strata. There are different rupture surfaces and slip as well as obviously different structural features of the Daxing Fault revealed in three shallow seismic reflection profiles. The two profiles(2-7 and 2-8)show obvious rupture surfaces, which are the expression of Daxing Fault in shallow strata. Along the profile(2-6), which is located at the end of the Daxing fault structure, a triangle deformation zone or bending fracture can be identified, implying that the Daxing Fault is manifested as bending deformation instead of rupture surfaces at its end section. This unique structural feature can be explained by a shearing motion at the end of extensional normal fault. Therefore, the Daxing Fault exhibits obviously different tectonic features of deformation or displacement at different structural locations. The attitude and displacement of the fault at the shallow part are also different to some extent. From the southwest section to the northeast section of the fault, the dip angle gradually becomes gentler(80°~60°), the upper breakpoint becomes deeper(160~600m), and the fault displacement in Neogene to Quaternary strata decreases(80~0m). Three shallow seismic reflection profiles also reveal that the Daxing Fault is a normal fault during Neogene to early Quaternary, and the deformation or displacement caused by the activity of the fault reaches the reflection layer T02. This depth is equivalent to the sedimentary strata of late Early-Pleistocene. Therefore, the geometry and morphology of the Daxing Fault also reveal that the early normal fault activity has continued into the Early Pleistocene, but the evidence of activity is not obvious since the late Pleistocene. The earthquakes occurring along the Daxing Fault, such as Daxing earthquake(M6¾)in 1057AD, may not have much relation with this extensional normal fault, but with another new strike-slip fault. A series of focal mechanism solutions of modern earthquakes reveal that the seismic activity is closely related to the strike-slip fault. The Daxing Fault extends also downwards into the lower crust, and may be cut by the steeply dipping new Xiadian Fault on deep seismic reflection profile. The northern section of the Daxing Fault strikes NNE, with a length of about 23km, arranged in a right step pattern with the Xiadian Fault. Transrotational basins have been developed in the junction between the northern Daxing Fault and the southern Xiadian Fault. Such combined tectonic features of the Daxing Fault and Xiadian Fault evolute independently under the extensional structure background and control the development of the Langgu sub-sag and Dachang sub-sag, respectively.  相似文献   

19.
The Zhuyangguan-Xiaguan fault is a major fault in the Nanyang Basin. Together with the the Shangxian-Danfeng fault in the south and the Tieluzi fault in the north, it serves as the north boundary of the East Qingling Mountains, as well as the dividing line between North China and South China blocks. This work studied the spatial extension, activity and shallow structure of Zhuyangguan-Xiaguan Fault by combination of shallow seismic exploration of three profiles across the fault and a composite drilling cross-section data. The anti-interference and high resolution shallow seismic reflection exploration method based on Vibseis techniques was used in the seismic survey. The results show the existence of the main fault and its southern branch. It can be determined that the the Zhuyangguan-Xiaguan fault is a NWW-trending normal fracture. The composite drilling cross-section reveals that the buried depth of the fault's up-breakpoint is about 17.6 to 20.5 meters and the latest active time is the late Middle Pleistocene. As one of the major buried faults in the Nanyang Basin, the Zhuyangguan-Xiaguan fault has restricted the development of Nanyang City for a long time due to its unclear location and activity characteristics. The results of this study can provide geological and geophysical evidence for seismic risk assessment and site selection for the major lifeline projects in Nanyang City.  相似文献   

20.
The Tan-Lu Fault Zone(TLFZ), a well-known lithosphere fault zone in eastern China, is a boundary tectonic belt of the secondary block within the North China plate, and its seismic risk has always been a focus problem. Previous studies were primarily conducted on the eastern graben faults of the Yishu segment where there are historical earthquake records, but the faults in western graben have seldom been involved. So, there has been no agreement about the activity of the western graben fault from the previous studies. This paper focuses on the activity of the two buried faults in the western graben along the southern segment of Yishu through combination of shallow seismic reflection profile and composite drilling section exploration. Shallow seismic reflection profile reveals that the Tangwu-Gegou Fault(F4)only affects the top surface of Suqian Formation, therefore, the fault may be an early Quaternary fault. The Yishui-Tangtou Fault(F3)has displaced the upper Pleistocene series in the shallow seismic reflection profile, suggesting that the fault may be a late Pleistocene active fault. Drilling was implemented in Caiji Town and Lingcheng Town along the Yishui-Tangtou Fault(F3)respectively, and the result shows that the latest activity time of Yishui-Tangtou Fault(F3)is between(91.2±4.4)ka and(97.0±4.8)ka, therefore, the fault belongs to late Pleistocene active fault. Combined with the latest research on the activity of other faults along TLFZ, both faults in eastern and western graben were active during the late Pleistocene in the southern segment of the Yishu fault zone, however, only the fault in eastern graben was active in the Holocene. This phenomenon is the tectonic response to the subduction of the Pacific and Philippine Sea Plate and collision between India and Asian Plate. The two late Quaternary active faults in the Yishu segment of TLFZ are deep faults and present different forms on the surface and in near surface according to studies of deep seismic reflection profile, seismic wave function and seismic relocation. Considering the tectonic structure of the southern segment of Yishu fault zone, the relationship between deep and shallow structures, and the impact of 1668 Tancheng earthquake(M=8(1/2)), the seismogenic ability of moderate-strong earthquake along the Yishui-Tangtou Fault(F3)can't be ignored.  相似文献   

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