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1.
Abstract On the basis of the records of strong seismic events taking place in soft carbonate sediments, a new seismic sequence system of vibrational liquefaction is established, which consists of a series of units, such as escaped structure of micrite veins and liquefied deformation formed in the period of seismic liquefaction, land subsidence structure after liquefaction, tsunamic hummocky and turbidite produced by seismic events, This sequence is a generalization and summation of field observation in vast areas, which shows the whole process of a strong seismic event and provides an unified theoretical explanation. The pattern of the seismic sequence by vibrational liquefaction provides one of correlation standards for geologists in the field to discriminate events in carbonate sequences. Based on the pattern of seismic sequence, the authors first advance a new conception of the Palaeo - Tanlu (Tancheng - Lujiang) Zone and discuss primarily its geological significations.  相似文献   

2.
碳酸盐岩振动液化地震序列   总被引:180,自引:16,他引:180  
乔秀夫  宋天锐 《地质学报》1994,68(1):16-34,T002
新建立的振动液化地震序列系碳酸盐软沉积物中的强地震事件记录,包括地震液化阶段产生的泄水脉、液化变形;液化停止后的地面下沉构造;地震引起的津浪丘状层与浊积岩等序列单元。这个序列来自大区域的野外实践总结,反映了一次强地震事件的全过程,并在理论上得到统一的解释。序列将为野外地质学家在碳酸盐层中识别事件提供对比的标准。根据振动液化地震记录,本文首次提出古郯庐带概念,并对其地质意义进行了初步讨论。  相似文献   

3.
中国震积岩研究综述   总被引:14,自引:1,他引:13  
震积岩是具有特殊震积构造和震积序列的一种灾变性事件岩。近十几年来国内外许多学者在研究、对比现代和古代震积岩成因沉积物后,逐渐认识到震积岩不同于其他类型的沉积岩,震积岩的主要识别标志有震裂缝、地裂缝、断裂递变层、微同沉积断裂、层内褶皱、假结核、液化砂(泥)岩脉、火焰构造及振动液化卷曲变形构造等。对中国震积岩和震积作用、地震——海啸序列、碳酸盐岩振动液化序列与萨布哈震积岩序列、震积岩与震积不整合序列、大陆边缘震积岩序列、陆相断陷湖盆震积岩及垂向序列等研究成果进行了综述。通过岩心观察和描述开展陆相震积岩研究具有重要的地质意义,特别是生油断陷湖盆震积岩的研究具有重要的石油地质意义。  相似文献   

4.
鲁中寒武系馒头组震积岩的发现及初步研究   总被引:25,自引:4,他引:25  
近几年在鲁中不同地区发现馒头组石店段中均有震积岩产出。震积岩形成于干燥的潮坪泻湖环境,发育在下寒武统的上部。它们具有记录强地震事件的泄水构造(地震成因泥晶脉)、液化卷曲变形、阶梯状小断裂、层内错断和液化网状裂纹等层内构造的特征。本文通过地层综合对比,论证了不同地区震积岩的等时性。认为:鲁中早寒武世末有一个地震活跃期;地震序列属乔秀夫(1994,2001a)提出的碳酸盐岩振动液化地震序列的原地系统;震积岩分布范围是约在510Ma前,以古郯庐带为震中的强地震之7-11度烈度区。为区别于张增奇(1996)提出的鲁中新元古代石旺庄期地震事件层,将此地震成因地层名之为馒头期地震事件层。  相似文献   

5.
塔里木盆地志留系震积岩特征及其意义   总被引:11,自引:3,他引:11       下载免费PDF全文
在区域构造背景研究和岩心观察的基础上,在塔里木盆地志留纪地层中识别出震积岩。震积岩的主要标志是发育各种类型的软沉积变形构造,包括微阶梯状正断层、层内小褶皱、扭曲变形、振动液化砂岩脉、震塌岩等。通过对中1井、顺1井、沙98井等岩心的系统观察,发现由于地震强度的不同,震积岩的垂向序列有所不同,地震越强烈,其震积岩序列的完整性越好,确定出震积岩的两种垂向序列。由于不同的震积岩构造特征对应不同的地震强度,因此进一步研究了各种震积岩构造与地震强度的关系。这些研究为塔里木盆地构造演化研究及震积岩的识别和描述提供了重要的地质理论依据,并可为研究该区古地震提供依据。  相似文献   

6.
介绍了辽宁太子河流域新发现的晚元古宙青白口系南芬组震积岩的层序。该层序为原地系统震积岩,由液化泥晶脉、震褶岩、震塌岩及地裂缝等组成。这是目前在我国所发现的最低层位碳酸盐岩振动液化地震事件记录。  相似文献   

7.
鲁西枣庄-临沂地区新元古界震碛岩的主要特征   总被引:7,自引:3,他引:4       下载免费PDF全文
鲁西枣庄—临沂地区新元古界碳酸盐岩系中,发育有由地震造成的同沉积构造现象,如微晶方解石脉、层内变形褶曲、层内微断层和内碎屑碳酸盐岩堆积等。野外实地观察、地质剖面测量和室内分析研究认为它们是由地震产生的强震动,使距震中一定范围的未固结沉积物经震动液化,震动变形形成的震积岩组合。根据其发育规律与组合特征,该地区震碛岩的形成应与古郯庐断裂在新元古代的活动密切相关。可初步确定为含有A、B和C3个震积岩单元的震动液化地震序列。  相似文献   

8.
东营凹陷现河地区沙三段震积岩特征及其意义   总被引:15,自引:3,他引:12  
在区域构造背景研究和岩芯观察的基础上,在东营凹陷现河地区沙三段地层中识别出震积岩。震积岩的主要标志是发育各种类型的软沉积变形构造,包括微阶梯状正断层、层内小褶皱、扭曲变形、振动液化砂岩脉、震塌岩等。通过对河152井、王59井、牛38井、牛22井等井岩芯的系统观察,发现由于构造和地震强度的不同,震积岩的垂向序列有所不同,并进一步研究了各种震积岩构造特征与地震强度的关系,研究表明不同的震积岩构造特征对应不同的地震强度,进一步确定了与古地震的关系。通过对本区储层分析,认为震积岩可以作为一种有效的储集空间。这些研究为东营凹陷构造演化研究、震积岩的识别和描述以及成藏提供了重要的地质理论依据,并可为该区古地震研究提供依据。   相似文献   

9.
国内震积岩研究现状   总被引:3,自引:0,他引:3  
地震是一种灾害性的地质事件。震积岩是在地层中具有古地震事件纪录的一类岩石的总称。对其研究可为地壳构造演化提供动力学解释。在地震过程中,震积作用可以形成特殊的标志性特征:如震动液化泥晶脉;微褶皱;层内阶梯状断层;自碎角砾岩(震塌岩);液化均一层等。本文综述了国内学者建立的几种陆相和海相震积岩序列:如碳酸盐岩振动液化地震序列(海相序列);大陆边缘震积岩序列;萨布哈震积岩序列(海陆过渡带序列);陆相碎屑岩地震液化序列(陆相序列)。同时,结合国内学者的研究成果,建立了由震积岩、海啸岩和震浊积岩组成的四种地震沉积组合;并指出了震积岩在构造演化解释、石油储层地质及全球古地震节律方面的研究意义。  相似文献   

10.
柴达木盆地西南缘新近纪以来受昆仑山断裂活动影响,地震活动强烈,发育一系列与地震活动有关的软沉积物变形构造,主要包括: 负荷构造、火焰构造、球—枕状构造、地震角砾、震裂缝、层内震褶曲和同沉积微断层等。通过区域地质调查、实测剖面、点上解剖和样品测试分析,初步认为柴达木盆地西南缘区分别于1.8—1.2,Ma、0.8,Ma、0.15,Ma发生过3次强烈构造活动,这些事件均伴随强烈的古地震活动,作为这些隆升事件的沉积和构造响应,盆地更新统中形成了一系列典型软沉积物变形以及相关的震积构造,对于研究青藏高原板内不均匀隆升过程及其隆升构造—地震—沉积效应具有重要意义。  相似文献   

11.
蒙古南贝尔凹陷白垩纪地震作用的证据   总被引:1,自引:0,他引:1  
王化爱  钟建华  隆锋 《沉积学报》2008,26(6):975-981
在区域构造背景研究和岩心观察的基础上,在蒙古南贝尔凹陷白垩纪地层中识别出震积岩。震积岩的主要标志是发育各种类型的软沉积变形构造,包括微同沉积断裂、卷曲变形构造、液化砂岩脉、震积枕状及伴生构造等,这是首次在蒙古南贝尔凹陷发现与地震作用有关的沉积特征。在塔21 9井中发现完整的震积岩垂向序列,序列自下而上分为下伏未震层、砂岩脉(砂火山)、震动卷曲变形层、内碎屑角砾岩层、阶梯状微断层和震裂缝层、震浊积岩层和上覆未震层。如此完整地震序列在同一口井岩芯中同时出现实属罕见,为进一步深入研究古地震作用提供了良好的物质组合。  相似文献   

12.
鄂尔多斯盆地上三叠统延长组长6 油层组是盆地内中生界最重要的含油层段之一。长6油层组以储集砂体发育、成因类型多样为特征。其中,位于湖盆中部的华池—庆阳地区在长6油层组沉积演化过程中广泛发育了一套与古地震事件有关的液化变形构造砂体。该地区长6油层组砂体中所发育的液化变形构造类型主要包括:负荷及砂球构造、振动液化卷曲变形构造、沙侵蘑菇、液化岩脉、液化摆动构造等。地震事件与重力滑塌所形成的变形构造的区别主要表现在:变形构造的优势方位、是否存在滑动面和是否存在均一化层。与古地震事件有关的液化变形构造砂体和其他成因类型砂体的叠置,主要包括两种类型:一为地震事件成因砂体与正常沉积作用所形成的砂体(三角洲前缘砂体)的叠置;二为地震事件成因砂体与由地震作用导致的三角洲前缘滑塌再搬运而形成的浊积砂体的叠置。最后,建立了不同沉积作用所形成砂体的成因模式。  相似文献   

13.
湖南慈利溪口震旦系陡山沱组震积岩的发现及其地质意义   总被引:1,自引:0,他引:1  
赵灿  李旭兵  李志宏  于玉帅  张华  刘安 《沉积学报》2012,30(6):1032-1041
湘西慈利溪口地区震旦系陡山沱组地层中首次发现碳酸盐岩原地震积岩。笔者通过剖面实测,详细观察和描述,结合构造背景,识别出阶梯状层内断层、液化碳酸盐岩脉、液化角砾岩、负荷构造以及微褶纹理等典型的震积软沉积变形构造的地质记录;震积序列在剖面结构上显示自下而上由下伏未震动层-阶梯状层内断层-微褶皱层-液化碳酸盐岩层-液化角砾岩层-上覆未震动层的渐变过程及震积作用逐渐衰减的趋势。震积岩发育的层位在时空上显示良好的可对比性,反映陡山沱期晚期构造活动强烈,并具备多旋回、多周期的特点。构造的活跃加速了有机碳库的氧化,为该时期多细胞生物的繁盛和大规模的成磷成矿作用奠定了基础;同时保存完好的震积地层记录对推断研究区的古沉积环境也具有重要意义。  相似文献   

14.
Three identical model boxes were made from transparent plexiglass and angle iron. Using the method of sinking water and according to the sedimentary rhythm of saturated calcium carbonate(lime-mud) intercalated with cohesive soil,calcites with particle sizes diameters of ≤ 5 μm,10–15 μm and 23–30 μm as well as cohesive soil were sunk alternatively in water of three boxes to build three test models,each of which has a specific size of calcite. Pore water pressure gauges were buried in lime-mud layers at different depths in each model,and connected with a computer system to collect pore water pressures. By means of soil tests,physical property parameters and plasticity indices(Ip) were obtained for various grain-sized saturated lime-muds. The lime-muds with Ip ranging from 6.3 to 8.5(lower than 10) are similar to liquid saturated silt in the physical nature,indicating that saturated silt can be liquefied once induced by a strong earthquake. One model cart was pushed quickly along the length direction of the model so that its rigid wheels collided violently with the stone stair,thus generating an artificial earthquake with seismic wave magnitude greater than VI degree. When unidirectional cyclic seismic load of horizontal compression-tension-shear was imposed on the soil layers in the model,enough great pore water pressure has been accumulated within pores of lime-mud,resulting in liquefaction of lime-mud layers. Meanwhile,micro-fractures formed in each soil layer provided channels for liquefaction dewatering,resulting in formation of macroscopic liquefaction deformation,such as liquefied lime-mud volcanoes,liquefied diapir structures,vein-like liquefied structures and liquefied curls,etc. Splendid liquefied lime-mud eruption lasted for two to three hours,which is similar to the sand volcano eruption induced by strong earthquake. However,under the same artificial seismic conditions,development of macroscopic liquefied structures in three experimental models varied in shape,depth and quantity,indicating that excess pore water pressure ratios at initial liquefaction stage and complete liquefaction varied with depth. With size increasing of calcite particle in lime-mud,liquefied depth and deformation extent increase accordingly. The simulation test verifies for the first time that strong earthquakes may cause violent liquefaction of saturated lime-mud composed of micron-size calcite particles,uncovering the puzzled issue whether seafloor lime-mud can be liquefied under strong earthquake. This study not only provides the latest simulation data for explaining the earthquake-induced liquefied deformations of saturated lime-mud and seismic sedimentary events,but also is of great significance for analysis of foundation stability in marine engineering built on the soft calcium carbonate layers in neritic environment.  相似文献   

15.
Numerous traces of paleoseismic events (seismites) were established in Mesozoic–Cenozoic marine sedimentary sequences of the northern Caucasus. These traces are most prominent in the terrigenous Middle Miocene sandy–clayey sediments. Impact of seismic shocks upon the relatively weakly lithified sediments provoked distortion of the primary sedimentary structure, liquefaction of the sandy material, and injections of different morphologies (neptunic dikes and sills). The formation of jointing in sediments fostered their vertical permeability and promoted the migration of diagenetic solutions into the adjacent horizons, which stimulated the formation of subvertical carbonate bodies. The amount and intensity of seismic events varied at different stages of the accumulation of sequences and in different areas of the paleobasin. In the eastern sector of the northern Caucasus, seismic activity similar to the present-day general pattern was likely developed as early as the Middle Miocene: maximum activity in the Dagestan and its westward attenuation. Traces of seismic activity are also recorded in the Maikopian (Oligocene–Lower Miocene) and Lower–Middle Jurassic rocks.  相似文献   

16.
2008年5·12特大地震中,位于甘肃省清水县郭川乡的田川村发生了饱和黄土的液化滑移灾害。本文首先在对田川场地进行考察的基础上,综合田川在汶川地震中的震害情况以及滑移区的地形条件,将该地区在汶川地震中的烈度进行了修正。其次对田川黄土进行了物性指标测试以及室内动三轴液化试验,根据试验结果,综合考虑产生液化所需的场地及土性条件、黄土的动强度和液化特性,对田川黄土液化灾害进行了分析,并采用反应分析的方法对其进行了液化判定。研究结果证明了田川黄土液化的事实存在性,为低烈度区黄土液化提供了新的震害依据。

  相似文献   

17.
TheNeoproterozoic,includingtheQingbaikouandSiniansystems,isweldevelopedintheeasternpartoftheSino-Koreaplate.InFig.1areshownth...  相似文献   

18.
At the end of May 2012, the Po plain region in northern Italy was shaken by a long sequence of seismic events. The 2012 Northern Italy earthquake sequence counted two mainshocks, about 1,600 aftershocks and lasted for several weeks. Although the mainshocks, which occurred on May 20 and May 29, 2012, registered a moment magnitude of 5.9 and 5.8, respectively, these two events caused widespread soil liquefaction and substantial damages to the built environment. This paper reports lessons learnt from a field investigation conducted in the areas affected by the earthquake sequence. Based on the field observations, it was concluded that despite the relatively low magnitudes of the shocks, most of the damages occurred as a consequence of liquefaction phenomena and/or absence of retrofitting of historical structures. The latter comprise churches, tower bells, towers, castles and fortresses. It was found that the occurrence of liquefaction was mainly associated with the presence of saturated alluvial soil deposits which were characterised by high liquefaction susceptibility. It was noted that these highly liquefiable soils were mainly located in proximity of ancient river courses that were artificially diverted in the eighteenth century to mitigate flooding and other hydrological risks.  相似文献   

19.
中国大陆科学钻探松科1井南孔青山口组二、三段岩心中发育有4段深水震积岩,赋存在青二段底部到青三段底部的深湖砂岩薄夹层中。标志性震积构造有阶梯状断层、震裂缝、角砾状构造、重荷构造、砂球-砂枕构造(假结核)、液化扭曲变形构造、肠状构造、液化砂岩脉、假泥裂,均属同生-准同生期的软沉积变形构造,缺少震浊积岩表明是原地震积岩。青山口组震积岩展示了震积岩的一个发育模式和沉积序列,该序列由地震作用强烈时期发育的液化变形下部单元和地震作用衰减时期发育的塑性变形上部单元构成。松科1井南孔青山口组中火山物质与火山灰夹层共生。在金6井、金65井相当层位有橄榄粗安岩、火山角砾岩发育,乾124井、乾109井有玄武岩发育,这些井均位于孙吴-双辽超壳断裂一线,表明在青山口期有构造-火山事件的发生,震积岩是构造-火山事件引发的地震在深水环境中的记录。松辽盆地青山口期有构造-火山事件的发生,显示坳陷阶段也存在相当规模的断裂活动和火山喷发。  相似文献   

20.
秦雅东  张士贞  刘函  李勇 《地球科学》2020,45(8):2945-2956
湖相沉积古地震研究是对地表破裂古地震研究的重要补充.通过详细的野外地质调查,在西藏许如错地区全新统湖相地层内新发现大量地震触发软沉积物变形构造(震积岩),层内发育液化脉、液化曲卷变形、液化角砾岩、液化水压构造、滴状体与锥状体、砾石丘、负载构造和火焰构造等软沉积变形标志,还发育同震断层、震裂缝和同震褶皱等同震构造标志.根据软沉积变形标志与震级之间的关系,结合历史地震统计液化颗粒范围,通过C14和光释光年龄测定,推测古地震事件发生在±7.5 ka,MS>7.5级;填补了该区历史地震的空缺,为恢复青藏高原南北向地堑地震活动历史及迁移规律提供了素材.震积岩中见大量砾石液化现象,这对现阶段以砂土-粉砂土研究为主的砂土液化调查工作提出了新挑战.   相似文献   

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