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在前人对福州盆地及其周缘活动断裂 1/ 1万填图研究的基础上 ,通过室内航卫片判读、野外详细调查等方法 ,经过详细论证 ,在福州盆地及周缘 6条活动断裂上选择了 11个认为可能是断层通过的位置 ,进行了探槽开挖。大部分探槽只揭露到了基岩中的断层 ,有些探槽在开挖深度内既没有揭露到基岩 ,在第四系中也没有揭露到断层。对于没有揭露到断层的探槽 ,认为断层没有错断开挖深度内的第四纪地层 ,以探槽最底部的地层年代作为断层最新活动时代的上限。有些探槽揭露到了基岩中的断层 ,这些断层向上没有错断第四系 ,就以上覆第四系底部的时代作为断层最新活动时代的上限。只有在沿桐口 -洪山桥断裂开挖的探槽中 ,揭露出 2条断层 ,它们向上都错断了相同层位的第四纪地层 ,并被更新的第四系所覆盖。根据测年结果 ,这些断裂不是全新世活动断裂 ,其中 ,闽侯 -南屿断裂可能为晚更新世活动断裂 ,其它断裂晚更新世以来都已不活动 相似文献
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鲁甸M_S6.5地震地表破坏及其与构造的关系 总被引：2，自引：1，他引：1
鲁甸6.5级地震造成了大量人员伤亡及房屋损毁,是云南近年来典型的"小震"致大灾现象。鲁甸地震后,针对重灾区龙头山镇开展了大量野外调查工作。调查涉及地震滑坡、地裂缝、断层剖面以及建(构)筑物震害等。调查发现,房屋损毁严重的龙头山镇政府所在地处在NW、NE向断裂交会部位;地震造成大量地质滑坡具有NE向优势分布特征,且与NE向展布的昭通-鲁甸断裂带关系密切;重灾区龙头山镇政府所在地地裂缝以NE向为主,龙头山镇南约6.5km的光明村大量地裂缝以NW向为主;同时,在光明村发现一系列NE、NW向断裂露头,疑似断层陡坎及槽谷,沿这些构造,在此次地震中均产生了裂缝或小位错。在野外调查基础上,结合余震序列分布及烈度等震线分布特征,认为此次地震由NW向包谷垴-小河断裂发震,同时大量NE向构造裂缝及滑坡等地质灾害显示不能完全排除NE向构造的作用。重要的是,地震地表裂缝和小位错与断裂的展布密切相关,有可能是地震同震地表破裂的表现。 相似文献
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通过对盐城、泰州地区浅层地震勘探工作,对盐城、泰州地区主要NE向断裂的第四纪活动性进行了研究,获得了以下认识：盐城-南洋岸断裂、南阳断裂展布于新构造强烈坳陷区,控制了新近系及第四系沉积;主断层倾向北,在浅部同时发育反向断层构成“Y”字型断层组合,为晚更新世活动断层,地震危险性较大,具有发生6.5级左右地震的构造背景;陈家堡-小海断裂和泰州断裂与本线路相交段最新活动时代为中更新世,在浅部各由2条北倾的正断层组成,分别组成高邮凹陷和溱潼凹陷南缘的铲式断阶带,对晚第四纪地层无明显影响。综合浅层地震勘探成果及新建盐泰锡常宜铁路周边地质资料分析,在工程线路范围内未发现活动断裂存在,可不考虑活动断裂地表错动对工程线路的影响。 相似文献
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西宁市北川河西岸断层、湟水断层活动性的钻探研究 总被引：1，自引：0，他引：1
本文主要根据《西宁市活断层探测与地震危险性评价》项目中跨断层钻探工作的初步结果,对西宁盆地河谷区两条主要的目标断层——北川河西岸断层、湟水断层的活动性予以阐述。通过对断层两侧钻孔岩芯的地层对比及年代学研究结果,建立跨断层柱状剖面,获得各地层层序主要界面的形成时代,并取得如下认识:北川河西岸断层在畜牧研究所场地并未断错到第四系覆盖层,晚更新世以来断层没有活动;湟水断层在彭家寨镇场地未断开第四系覆盖层,晚更新世晚期(约2万年)以来断层没有活动。 相似文献
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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
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乌鲁木齐拥有130余万人口,是新疆维吾尔自治区的政治、经济、文化、交通中心。乌鲁木齐市位于天山褶皱带与准噶尔盆地间的乌鲁木齐山前拗陷带上,是构造复杂、断裂纵横、活断层发育、有感地震较多并有破坏性地震伴随的构造部位。近几年来,在市郊多处不仅发现活断层断错第四系、断错冲洪积扇、断错山脊、断错水系,还发现地震地表断层、地裂缝、滑坡、塌陷及沙土液化等古地震遗迹。据历史地震资料,1934年8月7日东道海子6级地震震中距离市中心88km;人们记忆犹新的1965年11月13日博格达山6.5级地震震中,距离市中心45km,近30余年来,中小地震活动频繁。 导致强震发生的活断层在乌鲁木齐市区展布状况怎样?由于第四系和城市各种建筑设施 相似文献
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西山断裂是乌鲁木齐河以西一条颇具规模的断裂构造,控制着西山岭南麓,断裂从永光煤矿到红光山南长约37 km。断裂形成于中更新世期间,但整条断裂的形成过程可能并非同步,具有西老东新的特点,最新活动时代为晚更新世中晚期,为逆冲运动性质,断面北倾。该断裂在四道岔附近主断层及发育的一部分次级断层被第四系覆盖,研究该隐伏段对于以后城市土层合理利用和断层基本特征判断具有一定意义。目前高密度电法是探测隐伏断层的一种重要的物探方法,通过高密度电法对乌鲁木齐西山断裂隐伏段的探测,确定该断层隐伏段的位置及地层构造形态,为西山断裂深入研究提供一定依据。 相似文献
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The 1927 Gulang M8.0 earthquake has triggered a huge number of landslides, resulting in massive loss of people''s life and property. However, integrated investigations and results regarding the landslides triggered by this earthquake are rare; such situation hinders the deep understanding of these landslides such as scale, extent, and distribution. With the support of Google Earth software, this study intends to finish the seismic landslides interpretation work in the areas of Gulang earthquake (VIII-XI degree) using the artificial visual interpretation method, and further analyze the spatial distribution and impact factors of these landslides. The results show that the earthquake has triggered at least 936 landslides in the VIII-XI degree zone, with a total landslide area of 58.6 km2. The dense area of seismic landslides is located in the middle and southern parts of the X intensity circle. Statistical analysis shows that seismic landslides is mainly controlled by factors such as elevation, slope gradient, slope direction, strata, seismic intensity, faults and rivers. The elevation of 2 000-2 800 m is the high-incidence interval of the landslide. The landslide density is larger with a higher slope gradient. East and west directions are the dominant sliding directions. The areas with Cretaceous and Quaternary strata are the main areas of the Gulang seismic landslides. The X intensity zone triggered the most landslides. In addition, landslides often occur in regions near rivers and faults. This paper provides a scientific reference for exploring the development regularities of landslides triggered by the 1927 Gulang earthquake and effectively mitigating the landslide disasters of the earthquake. 相似文献
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根据地质、地貌、地球物理资料以及晚第四纪地层的分析对比，探讨了台湾海峡ＮＥ、ＮＷ向断裂的活动性及其与地震的关系。研究表明，以晚更新世晚期以来，上述断裂具有明显的活动性，海峡中５级以上地震大多发生在这些断裂附近或其交汇处。 相似文献
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兰州附近的庄浪河断裂和白银白杨树沟断裂是对兰州市地震安全有一定影响的晚第四纪活动断裂,但沿断裂发生的中强破坏性地震较为复杂甚至不明确。如何评价西部地区此类断裂的最大潜在地震震级及其危险性是地震中长期预测和地震区划研究中较为重要的问题之一。本文借鉴闻学泽等(2007)对中国大陆东部中-弱活断层潜在地震最大震级评估的思路,建立了兰州地区最大地震震级Mmax与断层小区震级-频度关系参数at/b值之间的经验公式;并采用经验公式外推得到庄浪河断裂和白杨树沟断裂的震级上限Mu分别为MS6.9、6.3,进而评估了这两条断裂的地震平均复发间隔和发震概率。 相似文献
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The Zhuanglang river and Baiyin Baiyangshu river faults are late Quaternary faults near Lanzhou city,which pose a threat to the safety of the city. However,the cause of medium-strong earthquakes along the fault is rather complicated and even uncertain. It is important for us how to assess the magnitudes of maximum potential earthquakes and the seismic risk of the faults. The authors make reference to the method that Wen Xueze,et al.(2007) developed to assess the magnitudes of maximum potential earthquakes in sub-areas of moderately and weakly active faults in the eastern Chinese Mainland,and brought forward an empirical relationship between the maximum magnitudes M_max and the a_t/b values of the sub-areas' frequency-magnitude relationships in the Lanzhou area. By using this empirical relationship,the authors have estimated the upper-limits M_u of the Zhuanglang river and Baiyin Baiyangshu river active faults near Lanzhou city as M_S6.9 and 6.3,respectively. In addition,they have assessed the average interval recurrence time and the probabilities of destructive earthquakes on the faults. 相似文献
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基于地震剖面解释的构造分析表明，河西走廊西段及邻区发育有许多晚第三纪-第四纪的逆断层与走滑断层. 其主要类型有两种:一是与北祁连逆冲推覆作用有关的南倾逆断层，其走向北西，主要分布于北祁连山东北缘及河西走廊西南部地区；二是与阿尔金断裂活动有关的逆断层与走滑断层，主要分布于红柳峡、宽台山——合黎山地区. 这些断层与新生代始新世末期以来印-藏碰撞的远距离效应有关. 它们于晚第三纪开始活动，主要活动于第四纪时期，而且大多目前仍在活动，属于活动性断层，是河西走廊地区地震的潜发因素. 此外，它们还造成了地层的强烈变形，形成了一系列的地貌阶地和河流的水平错移. 相似文献
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Introduction Hexi Corridor, a corridor extended over 1 000 km and with a strike of WNW-ESE, is locatedbetween Alxa uplift and northern Qilianshan Caledonian folding belt of northern Qinghai-Xizang(Tibet) Plateau (Figure 1). In the paper, we will discuss the regions between Altun fault and Yu-mushan of the western Hexi Corridor, where the climate is arid, which results in sparse vegetation,but abundant oil and gas resource, and being one of the most important petroleum industry base… 相似文献
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五峰山-西来桥断裂和丹徒-建山断裂是镇江地区2条主要的NW向断裂,可能与镇江多次破坏性地震相关。文中通过浅层地震勘探和钻孔联合剖面探测方法,对五峰山-西来桥断裂和丹徒-建山断裂的展布特征及第四纪活动性进行了系统研究。五峰山-西来桥断裂在浅层地震剖面上倾向NE,倾角约为60°,断距约为5~9m,以正断活动为主;大路镇场地上,该断裂断错的最新地层为中更新统底部,位错量为2m,判断五峰山-西来桥断裂的最新活动时代为中更新世早期。丹徒-建山断裂在浅层地震剖面上倾向SW,倾角约为50°~55°,断距约为2~7m,以正断活动为主;访仙镇场地上,中更新统之上的地层没有被断错的迹象,中更新统底部可能被断层影响,判断丹徒-建山断裂的最新活动时代为早更新世—中更新世早期。 相似文献
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Thrust geometries in unconsolidated Quaternary sediments and evolution of the Eupchon Fault, southeast Korea 总被引：1，自引：0，他引：1
Young-Seog Kim Joon Young Park Jeong Hwan Kim Hyeon Cho Shin David J. Sanderson 《Island Arc》2004,13(3):403-415
Abstract The Korean peninsula is widely regarded as being located at the relatively stable eastern margin of the Asian continent. However, more than 10 Quaternary faults have recently been discovered in and reported from the southeastern part of the Korean Peninsula. One of these, the Eupchon Fault, was discovered during the construction of a primary school, and it is located close to a nuclear power plant. To understand the nature and characteristics of the Quaternary Eupchon Fault, we carried out two trench surveys near the discovery site. The fault system includes one main reverse fault (N20°E/40°SE) with approximately 4 m displacement, and a series of branch faults, cutting unconsolidated Quaternary sediments. Structures in the fault system include synthetic and antithetic faults, hanging‐wall anticlines, drag folds, back thrusts, pop‐up structures, flat‐ramp geometries and duplexes, which are very similar to those seen in thrust systems in consolidated rocks. In the upper part of the fault system, several tip damage zones are observed, indicating that the fault system propagates upward and terminates in the upper part of the section. Pebbles along the main fault plane show a preferred orientation of long axes, indicating the fault trace. The unconformity surface between the Quaternary deposits and the underlying Tertiary andesites or Cretaceous sedimentary rocks is displaced by this fault with a reverse movement sense. The stratigraphic relationship shows normal slip sense at the lower part of the section, indicating that the fault had a normal slip movement and was reversely reactivated during the Quaternary. The inferred length of the Quaternary thrust fault, based on the relationship between fault length and displacement, is 200–2000 m. The current maximum horizontal compressive stress direction in this area is generally east‐northeast–west‐southwest, which would be expected to produce oblique slip on the Eupchon Fault, with reverse and right‐lateral strike‐slip components. 相似文献