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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
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龙泉山活动断裂带及其潜在地震能力的探讨 总被引：10，自引：0，他引：10
本文根据测龄样品的断代分析、地壳形变测量以及沿断裂带的地震活动等对龙泉山断裂带的活动性进行了讨论。并根据断层的几何结构分段特征，运用活断层长度与地震震级的关系，探讨了该断裂带的潜在地震能力。结果表明，龙泉山断裂带属一条中、晚更新世有活动的断裂带。有历史地震史料记载以来，发生最大的一次地震是１９６７年仁寿大林场５．５级地震，近代地震活动主要以中、小地震活动为主，因此该断裂带属一条中强活动断裂带。从地震活动看，断裂带中南段的活动强度相对北段要大；西坡断裂的活动强度又大于东坡断裂，且西坡断裂具有较明显的分段活动特征。该断裂带上未来可能发生地需的最大震级为５．５±０．５级。 相似文献
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在野外考察的基础上 ,结合所采集的各条断裂之上的覆盖物或断层带物质的热释光 (TL)或电子自旋共振 (ESR)样品年龄 ,对龙门山断裂带北段的晚第四纪活动性进行了分析 ,认为 :后山断裂在第四纪早 -中期曾有过活动 ,晚更新世以来已不再活动 ;中央断裂早更新世或前第四纪是活动的 ;前山断裂在白龙江以北变成一些小的、零星分布的断裂 ,它们在第四纪早期以前有过活动。而已有研究表明龙门山断裂带中段和西南段晚第四纪以来仍在活动。造成龙门山断裂带不同段落新活动时代不同的主要原因 ,可能是区域应力场的变化所导致的活动地块边界的变化。龙门山断裂带的北段现在已不构成活动块体的边界 ,加之岷山隆起对龙门山断裂带东北段的屏障作用 ,使得龙门山断裂带北段活动减弱。而龙门山推覆构造带中南段和岷山隆起构造带共同成为块体持续挤压作用的东界。这为研究青藏高原的运动学及动力学等问题提供了重要信息 相似文献
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临潼-长安断裂带晚第四纪以来的活动性 总被引：1，自引：0，他引：1
对临潼-长安断裂带进行了详细的野外调查,以期掌握其最新活动年代和第四纪以来的活动特征。该断裂总体走向NE,以张性垂直运动为主,断面明显错断了黄土中的第1层古土壤S1,说明其晚更新世以来仍在活动,并且北段和中段的活动性比南段强,但是错距大多<2m,滑动速率较小,考虑到临潼-长安断裂带由多条次级断层组成,其整体活动性应该比我们计算得到的局部断层滑动速率大得多。断层错距自上而下成递增趋势,并且根据不同地层年代计算出的滑动速率基本一致,因此该断裂带自中更新世晚期以来极可能以垂向蠕滑活动为主 相似文献
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本文构建一种应用有限元开展特征地震数值模拟的新方法, 并以龙门山断裂带中段的浅层构造和动力学机制为背景, 研究了平行逆冲断层分布格局对区域地震活动性的影响. 结果表明, 从断层活动相互影响的角度看, 包含3条平行逆断层的断裂带的整体地震活动性并不适用严格周期的特征地震模型, 当断层间距在20 km以下时, 随着断层间距的缩短, 对单条断层应用特征地震模型的适用性会逐渐降低. 龙门山断裂带中段的模拟计算结果显示, 后山断裂的地震活动相对独立, 区域活动性和中央断裂的断层活动很可能不适用严格周期的特征地震模型. 相似文献
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《地震地质》2017,(4)
安丘-莒县断裂(F_5)为郯庐断裂带中段东地堑内最新活动断裂。近年来,F_5江苏段研究成果丰硕,发现不同地段普遍存在全新世活动性,运动方式以右旋走滑兼挤压逆冲为主。以往研究未讨论过F_5在淮河以南安徽境内的延伸情况以及进一步的活动性问题。文中选取与F_5江苏段线性影像特征延伸一致的淮河南岸郯庐紫阳山段作为突破口,通过遥感影像解译、地质地貌调查和探槽开挖,初步得到以下认识:1)紫阳山段线性构造地貌特征清晰,断层发育于浮山至紫阳山一线的中生代红色砂岩隆起边缘缓坡,为安丘-莒县断裂(F_5)过淮河后的南延部分;2)朱刘探槽开挖揭示,该段错断了晚更新世晚期黏土层,晚更新世晚期—全新世早期黑色黏土层受断层活动影响沿断面灌入、填充,形成黑色断层条带及黑土充填楔,表明断层最新活动时代达全新世早期;3)朱刘探槽开挖揭示,该段第四纪以来存在至少3次古地震事件,第1次古地震事件推测年代为第四纪早、中期,第2次古地震事件年代为20.10~13.46ka BP,第3次古地震事件年代为(10.15±0.05)~(8.16±0.05)ka BP。上述研究成果弥补了对郯庐断裂带安徽段晚第四纪活动性认识的不足,为安徽省的地震监测和震害防御工作提供了基础数据。 相似文献
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郯庐断裂带安徽省内段落属于该断裂带的南段,断裂构造复杂,总体上断层活动性要弱于断裂带的山东、江苏段。近年来笔者多次在苏皖交界地区开展野外地质地貌调查,发现淮河南北两侧的地形地貌存在较大差异。本研究以淮河以南的郯庐断裂带东支断裂明光段为探查重点,在明光紫阳山北侧跨断层开挖地质探槽。探槽(Tc1)显示断层表现为逆冲、张裂等活动形式,且断层向上延伸错动晚第四纪地层;结合年代样品测试结果,表明该段断层晚第四纪以来有较强的活动,最新活动时代可达晚更新世-全新世早期;探槽揭露的断层表现出多种活动形式,显示了明光段断层活动的多期次性和区域构造应力场的复杂性。 相似文献
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在山东半岛北部近海海域进行了多条剖面的声波探测，初步查明了蓬莱－威海断裂带的基本活动特征.该断裂带由一系列北西走向的次级断层组成，主体在长岛至大竹岛之间的海域，多数断层以正断兼有走滑运动为主，部分断层具有逆冲运动性质.断裂带在第四纪活动明显，以北东向桃村-东陡山断裂在海域的延伸段为界，蓬莱-威海断裂带可分为两段：长岛-烟台段和烟台-威海段.西段长岛-烟台段为晚更新世活动段，多数次级断层上断点埋深位于海底以下30m，明显错断了中更新世地层，部分断层明显错断了晚更新世早期地层，有些断层达到晚更新世地层中部，但没有发现全新世地层错动现象.东段烟台-威海段为中更新世活动段，没有发现晚更新世地层错断现象.蓬莱-威海断裂带对历史地震和现代小震活动具有明显控制作用，其中1548年7级地震发生于断裂带西段，1948年6级地震发生于断裂带东段.蓬莱-威海断裂带与北东向断裂交汇区是中强地震发生的有利部位. 相似文献
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Daliangshan fault zone (DFZ) constitutes an indispensable part of Xianshuihe-Xiaojiang fault system which is one of the main large continental strong earthquake faults in China.Puxiong Fault,the east branch of middle segment of DFZ,is the longest secondary fault.Its paleoseismic activity plays an important role in evaluating regional seismic activity level and building countermeasures of preventing and reducing the earthquake damage.The active fault mapping as well as the study of paleoseismological trench in recent years illustrates that Puxiong Fault is a slightly west-dipping high-angle left-lateral strike-slip fault with strong activity since late Pleistocene.Two trenches excavated across this fault reveal 2 and 3 paleoearthquakes that ruptured the fault at 8206 BC-1172 AD,1084-1549 AD,and 17434-7557 BC,1577-959 BC and 927-1360 AD,respectively.The OxCal model combining the results from both trenches and the another one in previous study across the fault with the historical earthquake record yields the elapsed time of~0.7ka of the latest paleoearthquake event,and the interval time is~2.3ka between the last two events.In the model,the penultimate event is considered to be recorded in all trenches.As all the three trenches are located at north part of the Puxiong Fault whose strike is apparently different from the south part,the~57km long north secondary segment is supposed to be the seismogenic structure of the paleoearthquake.According to the empirical scaling laws between magnitude and rupture length,the magnitude of the surface ruptured paleoearthquake is estimated to be more than M7 with the coseismic displacement~3.5m.However,the difference between the time of the paleoearthquake events on the middle and south segments of DFZ illustrates their independence as earthquake fracture units,and furthermore,the lower connectivity and the new generation of DFZ. 相似文献
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通过中越两国对越南红河断裂带开展的联合野外考察,获取了地震、地质、地貌和年代学等反映该断裂最新活动的相关证据。综合研究表明,越南红河断裂带第四纪以来的右旋走滑活动延续和保持了在中国境内自北向南逐渐减弱的总体趋势。其第四纪主要活动时代为中更新世中晚期,且总体活动水平明显低于中国云南境内部分,特别是自晚更新世以来越南红河断裂带的活动已表现得十分微弱。结合断裂现今地震活动和区域GPS大地形变特征分析认为,自晚第四纪以来,来自青藏高原的"侧向挤出"动力作用对红河断裂右旋走滑活动在时间、空间和强度等方面的影响可能非常有限。文中还探讨了造成这一有限影响可能的大地构造和深部构造原因 相似文献
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基于钻探的芦花台隐伏断层晚第四纪活动特征 总被引：1，自引：0，他引：1
The Luhuatai fault is one of the important buried tectonics in the Yinchuan basin. Based on the results of shallow seismic exploration, we conducted composite drilling section exploration and dating of the samples from boreholes. Some useful data was obtained, such as the depth of the upper breaking point, the latest activity age, displacement in the late Quaternary, and slip rates, etc. This study shows that the activity is different between the north and south segment along the Luhuatai fault. The north segment is a Holocene fault, while the south segment is a late mid-Pleistocene fault. From north to south along the north segment of Luhuatai fault, the activity has been enhanced, and the faulting is stronger in late Pleistocene than Holocene. 相似文献
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Anqiu-Juxian Fault is an important fault in the Tanlu fault zone, with the highest seismic risk, the most recent activity date, and the most obvious surface traces. Due to lack of credible geological evidences, there is big controversy on the Holocene activity in the Jiangsu segment of this fault. Research on the characteristics of late Quaternary activity in the Jiangsu segment of Anqiu-Juxian Fault, particularly its latest activity time, is of great significance to assessment of its earthquake ability and seismic risk. Based on field investigations on the Jiangsu segment of Anqiu-Juxian Fault, and combining with the results of fault activities identification on this fault in Suqian City, we discussed the characteristics of its activities in late Quaternary. Multiple geological sections we found in this study and the results of fault activities identification in Suqian City all indicate that there was an ancient seismic event occurring in middle period of Holocene in the segment from southern Maling Mountain to Suqian City; but the trench at Houchen village did not show any evidence of Holocene activity on the Chonggangshan segment of this fault. Based on method of shallow seismic exploration, we carried out a systematic exploration of this fault to get its accurate position and activity characteristics. The results show that Anqiu-Juxian Fault in Suqian City is mainly characterized by dextral strike-slip, associated with both thrusting and extensional movement in different positions. A series of low hills were formed along the fault in the north of Suqian City, and a small graben basin was formed in the south of Suqian City, both are controlled by the dextral strike-slip movement of this fault. The Jiangsu segment of Anqiu-Juxian Fault in general is characterized by dextral strike-slip with thrusting movement. But some parts of it are characterized by dextral strike-slip with extensional movement. The Jiangsu segment of Anqiu-Juxian Fault experienced a number of activities since the late Quaternary, with an obvious activity in Holocene. The seismic activities of Jiangsu segment of Anqiu-Juxian Fault have the characteristic of high intensity and low frequency. Its activities decrease gradually from north to south as a whole. 相似文献
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THE STRUCTURAL CHARACTERISTICS OF PANGUSI-XINXIANG FAULT IN THE SOUTHERN MARGIN OF TAIHANG MOUNTAINS 
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下载免费PDF全文 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
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YANG Yuan-yuan ZHAO Peng ZHENG Hai-gang YAO Da-quan WANG Xing-zhou MIAO Peng LI Jun-hui WANG Xiao-li SHU Peng 《地震地质》2017,39(4):644-655
Anqiu-Juxian Fault(F5) is the latest active fault in the eastern graben of the middle segment of the Tanlu fault zone. In recent years, the research results of F5 in Jiangsu Province are abundant, and it is found that Holocene activity is prevalent in different segments, and the movement pattern is dominated by dextral strike-slip and squeezing thrust. The Anhui segment and the Jiangsu segment of the Tan-Lu fault zone are bounded by the Huaihe River. Previous studies have not discussed the extension and activity of F5 in the south of the Huaihe River in Anhui Province. This paper chooses the Ziyangshan segment of Tanlu fault zone in the south of the Huaihe River as the breakthrough point, which is consistent with the linear image feature of extension of F5 in Jiangsu Province. Through the remote sensing image interpretation, geological and geomorphological investigation and trench excavation, we initially get the following understanding:(1)The linear structural features of the Ziyang segment are clear, and the fault is developed on the gentle slope of the Mesozoic red sandstone uplift along the Fushan-Ziyangshan, which is the southern extension of the Anqiu-Juxian Fault(F5); (2)The excavation of the Zhuliu trench reveals that the late Pleistocene clastic layers are interrupted, and the late late Pleistocene to early Holocene black clay layers are filled along the fault to form black fault strips and black soil-filled wedges, indicating that the latest active age of the fault is early Holocene; (3)The excavation of Zhuliu trench reveals that there are at least 3 paleo-earthquake events since the Quaternary, the first paleo-seismic event is dated to the early and middle Quaternary, and the 2nd paleo-seismic event is 20.10~13.46ka BP, the age of the third paleo-seismic event is(10.15±0.05)~(8.16±0.05)ka BP. These results complement our understanding of the late Quaternary activity in the Anhui segment of the Tanlu fault zone, providing basic data for earthquake monitoring and seismic damage prevention in Anhui Province. 相似文献
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实地调查表明,山西长治断裂由三段组成,南段和中段为西倾正断层,北段为东倾正断层,总体走向北东25o,长达65km,控制着附近山地与第四纪山间盆地的构造演化和地貌发育;第四纪早期,断裂发生强烈的垂直差异活动,最大垂直活动幅度可达400m左右;第四纪晚期,断裂活动性明显减弱,中段仍有活动,至少发生过两期活动,第—期活动发生于距今10.88万年左右或以后、1.49万年以前,第二期活动发生于距今1.49万年以后,垂直错距0.65m。 相似文献