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1.
城市地球物理探测面临众多人文挑战,像城市交通、密布电网、参差楼群等,对应用不同方法进行数据处理分析提出了技术挑战,需要用创新的方式和技术进行城市探测。为探索和发展适用于城市地下空间资源开发利用的地球物理探测新技术,中国地质科学院地球深部探测中心第一次启动了城市地下空间勘查评价试点工程,并选择济南市作为试点城市,试验短周期密集台阵噪声层析技术,并取得了较好成效。获得的主要认识如下：(1)在非弥散场或非均匀噪声场源的人文干扰较为严重的城市区域,通过长时间的噪声信号的采集,可获得高信噪比的面波信号,因此密集台阵噪声成像技术适应于城市地下空间的背景岩层结构探测工作。(2)本次研究提取出了周期范围为0.2～1.5 s的高信噪比面波信号,并取得与实际地质特征相一致的横波速度结构信息。(3)从横波速度结构特征来看,研究区300 m以浅,主要岩性为灰岩且主要分布于研究区西侧,而侵入岩体主要分布于东侧,中间存在一个明显的分界面,指示存在一个近南北向的隐伏断裂。随着深度的增加,大面积的侵入岩体展布于深层,灰岩只在北侧局部有显现。总体来说,本项研究证明了密集台阵噪声层析方法能够适用于人文干扰严重的城市地下空间背景岩层结构探测,这一成果对认识研究区地下结构、地震防灾、工程应用具有重要指导意义。 相似文献
2.
Germán A. Prieto Marine Denolle Jesse F. Lawrence Gregory C. Beroza 《Comptes Rendus Geoscience》2011,343(8-9):600-614
The use of the ambient seismic field (ASF) to extract Earth's response has received significant attention in the last several years. Multiple studies demonstrate the utility of the ASF for estimating high-resolution velocity models in various locations. In this paper, we discuss the amplitude information carried by the ASF. Amplitude information includes both amplification effects due to elastic structure, such as low velocity sedimentary basins, and attenuation effects in the crust and upper mantle or even in buildings. As has been suggested by other authors, amplitude measurements may be biased due to non-uniformities in ambient field excitation; however, we find very similar and stable results for different time intervals for both amplification and attenuation, suggesting that this bias may not be as large as feared. We conclude that valuable amplitude information can be recovered from the ASF through careful processing. Amplitude measurements may be particularly valuable due to the enhanced sensitivity of attenuation to fluids and/or temperature fluctuations. 相似文献
3.
A. A. Mohamed M. A. El-Eraki A. A. El-Kenawy S. I. Mostafa 《Arabian Journal of Geosciences》2016,9(13):617
This study uses the seismic refraction and noise measurements to investigate the velocity structure of the subsurface and emphasize the advantage of ambient vibration over the conventional seismic refraction technique. Field measurements were carried out at nine sites in and around Zagazig city. Shallow seismic refraction data were interpreted using the delay time method to obtain the two-dimension ground model at each site. Ambient vibration arrays are used to infer the one-dimensional compressional and shear wave velocity profiles through two main steps. The first step is to derive the dispersion curve from the recorded signals using the frequency-wavenumber method. The second is to invert the dispersion curve to obtain the site velocity profiles. The results of the compressional wave velocities obtained from seismic refraction technique showed that the subsurface consists of a number of layers ranging from two to four layers and give a good agreement with the results of the seismic wave velocities obtained from the ambient vibration arrays. The ambient vibration arrays gave a deeper depth of penetration than the other method, providing more information on the subsurface structure without any disturbance to the environment. This work provides reliable estimates of the seismic velocity structures of both shallow and deep sedimentary layers within the area of interest. 相似文献
4.
《Comptes Rendus Geoscience》2014,346(11-12):307-316
We analyze the sensitivity of cross correlations to the anisotropy of the incident field in the context of seismic ambient noise monitoring of small velocity changes. Numerical simulations of elastic waves are performed in a 2D scattering plate with a focus on the comparative character of the direct and coda waves in the cross-correlation. We show that coda waves reconstructed from cross-correlations are far more robust than direct waves in the presence of azimuthal anisotropy of the incident field. We observe similar behavior with real data recorded on Erebus volcano, where a database of impulsive icequakes is used to simulate an anisotropic source field. We propose a simplified approach to evaluate the sensitivity of scattered waves to the anisotropy of the incoming noise field. We rely on previous results obtained for direct waves and on intrinsic properties of scattered waves to predict the errors produced by strong source anisotropy with numerical experiments. These results also yield realistic values for monitoring the accuracy to be expected with real data at crustal scales. Our analysis shows that high-precision noise-based monitoring could be performed with coda waves in the correlation functions, even in the presence of variations in the azimuthal distribution of the ambient noise field. 相似文献
5.
6.
Through analysis of seismic ambient noise recorded by the GHENGIS array, we constructed a high‐resolution 3‐D crustal shear‐wave velocity model for the central Tien Shan. The obtained shear‐wave velocity model provides insight into the detailed crustal structure beneath the Tien Shan. The results obtained at shallow depths are well correlated with known subsurface geological features. Low velocities are found mainly beneath sedimentary basins, whereas high velocities are mainly associated with mountain ranges. At greater depths of ~43–45 km, high velocities were observed beneath the Tarim Basin and Kazakh Shield; these high velocities extend forward in opposite directions and tilt down towards the central Tien Shan to a depth of in excess of 50 km, most likely reflecting lateral variations in crustal thickness beneath the Tien Shan and surrounding platforms. 相似文献
7.
The technique to retrieve Green’s functions by cross-correlation of seismic noise that is now often referred to as seismic interferometry opened the way to a completely new type of seismological observation – the continuous monitoring of changes in the subsurface medium. In this paper we review Passive image interferometry (PII) as the technique that makes use of the possibility to repeatedly retrieve Green’s functions in order to precisely infer medium changes by comparing Green’s functions that are retrieved at different times. PII is capable of identifying velocity changes below 0.1% and was applied successfully in different tectonic situations. We review three investigations of PII that demonstrate the wide range of possible applications. The first application that introduced the concept of PII in 2006 revealed hydrology related changes of subsurface velocity at Merapi volcano. The second application we present was the first noise based observation of co-seismic changes. And we finally review a recent investigation that documented velocity variations in the shallow subsurface of the moon. 相似文献
8.
物源体系分析是沉积盆地特征分析的重要内容，为进一步阐明珠江口盆地恩平凹陷恩平组的沉积特征和物源体系，本文拟利用恩平凹陷的三维地震资料和钻井数据，通过古生物环境分析和锆石U- Pb定年等方法，并借助地震剖面中古沟谷的识别、前积反射结构、地震多属性分析结果和沉积相带平面分布特征，对恩平凹陷恩平组物源体系特征进行综合分析。研究结果表明，恩平组PSQ1～PSQ2时期表现位明显的陆相湖盆特征，物源主要为珠江口盆地内隆起的古生代变质岩和中生代火成岩基底，少量来源于北部华南褶皱带的元古宙变质岩；随着PSQ3时期断层活动逐渐停止，湖平面不断上升，华南褶皱带物源供给能力明显增强，逐渐成为恩平凹陷主要物源。鉴于目前南海北部缺少陆相湖盆地层的完整岩芯剖面，制约了南海北部裂陷期构造- 沉积耦合研究并影响了该地区的油气勘探，建议下一步在南海北部陆相沉积盆地(如珠江口盆地)开展大洋钻探工作，以便获取更连续、时间精度更高，受风化作用影响更小的陆相湖盆地层的完整岩芯剖面。这不仅有利于指导下一步油气勘探，也可通过重建陆相沉积盆地不同地质历史时期的沉积变化过程，为了解古气候状态和预测未来气候变化提供重要依据。 相似文献
9.
Since plate tectonics has been linked to material flow in the Earth's mantle, it is commonly accepted that convective motion in the sublithospheric mantle results in vertical deflections and horizontal plate motion on the Earths surface. Those mantle flow-driven vertical deflections are recognized through significant signals and traces in the sedimentary records (unconformities and missing sections). Recently, Friedrich et al. (2018) introduced an event-based plume stratigraphic framework that uses such signals in the stratigraphic record to detect the geological evolution near, and on the Earth's surface in areas of interregional scale caused by mantle plume movement. Information about these dynamic processes is stored in geological archives, such as (1) stratigraphic records of sedimentary basins and (2) thermochronological data sets of igneous, metamorphic, and sedimentary rocks.For the first time, this research combines these two geological archives and applies them to the Mesozoic SW Gondwana intraplate environment to retrieve the Paraná-Etendeka plume movement prior to the Paraná-Etendeka LIP. We compiled 18 stratigraphic records of the major continental and marine sedimentary basins and over 35 thermochronological data sets including >1300 apatite fission-track ages surrounding the Paraná-Etendeka Large Igneous Province to test the event-based plume stratigraphic framework and its plume stratigraphic mapping to retrieve the timing and spatial distribution of the Paraná-Etendeka plume.The plume stratigraphic mapping, using the stratigraphic records is suitable to demark a possible plume center, plume margins and distal regions (Friedrich et al., 2018). Thermochronological data reveal centers of a significant thermal Paraná-Etendeka plume influence. Both archives show significant signals and traces of mantle plume movement well in advance of the flood basalt eruptions. Our LTT data combined with stratigraphic records are modeled successfully with respect to a viable mantle plume driven thermal evolution and therefore, we suggest that thermochronological data, in combination with stratigraphy records have the potential to retrieve the Paraná-Etendeka plume movement. 相似文献
10.
岩浆活动在沉积盆地中是非常广泛的.随着油气勘探领域的扩展,对沉积盆地火成岩及相关构造的研究愈加重要.沉积盆地火成构造是指在沉积盆地中由岩浆侵入或喷发作用形成的岩浆和围岩及上覆层变形构造的总和.当前,利用三维地震数据研究岩席的几何学与侵位机制取得了重要进展,开启了沉积盆地火成构造研究的新时代.三维地震分析是沉积盆地火成构... 相似文献
11.
地震干涉技术可以将任意2个检波器接收到的数据合成为在若干检波器之间传播的波,就好像其中的一个检波器作为一个虚拟震源来发挥作用。它可以从混沌无序的地震信号中发现有用信息,从地震噪声中提取有用信号以此推断地震波穿过介质的地质构造。基于反褶积算法,对其理论公式进行了较详细的推导,实现被动源地震干涉成像,证明了反褶积算法的可行性;并将其结果与互相关算法的结果进行对比,分析了2种方法在信噪比和分辨率方面的差异。数值计算表明,反褶积算法的纵向分辨率比互相关算法的高。对其进行的加噪试算表明,震源叠加后的反褶积算法呈现出高信噪比的特点。 相似文献
12.
地质历史中板块构造启动时间 总被引：1，自引：0，他引：1
赵振华 《大地构造与成矿学》2017,41(1):1-22
地质历史中板块构造是何时开始启动的长期存在着激烈的争论,最极端的一是认为板块构造在新元古代的800 Ma前开始,二是在冥古宙4.3 Ga就已启动,多数学者认为在太古宙末开始启动。确定板块构造启动时间主要依据以下几方面:(1)地球动力学特点,如地幔的热状态以及粘塑性地幔对流模拟表明,板块构造可能是在地球热和冷停滞状态之间演化的一个相。在太古宙较热的地球中,板片强度低,板片的频繁断离阻止了形成类似现代样式的长期俯冲体系,太古宙的板块构造是短期的、阵发性的;(2)代表俯冲的标志的蛇绿岩、蓝片岩和超高压(UHP)变质地体;(3)具有弧特征的岩石组合,如拉斑玄武岩-安山岩-英安岩-流纹岩及英云闪长岩-奥长花岗岩-花岗闪长岩(TTG)岩套;(4)增生楔中混杂岩和大洋板块地层、前陆盆地、大陆裂谷、双变质带、造山带;(5)与俯冲带关系密切的造山型Au矿、斑岩Cu矿和浅成热液矿床、火山岩型块状硫化物矿床(VHMS),它们最早出现的年龄一致在3.5~3.1 Ga,指示了板块构造的开始;(6)世界不同地区大陆的Ni/Co、Cr/Zn比值随沉积年龄变年轻而降低,陆壳从3.0 Ga前的镁铁质转变为2.5 Ga时的长英质,表明全球板块构造的启动应在3.0 Ga的古中太古代;(7)冥古宙锆石、太古宙金刚石中矿物包裹体及Hf、O、C、N同位素组成研究表明,冥古宙地球表面存在类似板块汇聚边缘,太古宙含有大陆沉积物的海洋岩石圈俯冲进入地幔。 相似文献
13.
海中地区火成岩发育，为含油层序，但地震地质条件复杂，受火成岩影响资料品质较差，火成岩与地层解释有较大难度。笔者应用测井、地球物理方法结合钻井资料，重点介绍利用火成岩的高速、高阻抗特征，应用STRATA测井约束反演对火成岩进行地震识别；应用EMERGE孔隙度反演技术，预测火成岩厚度与孔隙度。 相似文献
14.
A. V. Maslov G. A. Mizens V. N. Podkovyrov E. Z. Gareev A. A. Sorokin Yu. N. Smirnova T. M. Sokur 《Lithology and Mineral Resources》2013,48(1):74-97
Some lithochemical features of sandstone associations formed at the orogenic stage of the evolution of mobile belts are analyzed on the basis of literature and original data along with the wide application of discrimination diagrams. Psammites of the flysch and molasse formations of foreland basins, as well as sand-stones from intermontane troughs and postcollisonal grabens, are considered synorogenic sediments. Analysis of the chemical composition showed that sandstones were formed by the mixing of clastic material from heterogeneous (proximal included) source areas. In discrimination diagrams, the compositional fields of sandstones are variable, because they were derived from diverse igneous, metamorphic, and sedimentary rocks of different geodynamic settings. Hence, data based on the generally accepted discrimination diagrams cannot be considered as the single (decisive) argument for establishing the geodynamic nature of sandstones without the consideration of textural-structural features of rocks and the analysis of geological structure of sedimentary associations therein. 相似文献
15.
鄂尔多斯盆地矿产资源丰富,是我国陆上第二大沉积盆地,加快该盆地矿产资源的勘探工作,对推进我国中西部能源基地建设,缓解我国当前能源危机问题有非常重要的现实意义。但是,由于该地区大部分处于黄土高原,地表条件复杂,表层岩性变化剧烈,地震勘探一直是难点。本文以姬塬地区为例,针对地震勘探难点,对黄土塬变化多样的地表地震及复杂的地下地质条件进行了综合分析,综合应用层析静校正、时空转换、反褶积等复杂地区地震资料处理技术,取得了较好的处理效果,提高了信噪比,可以为类似条件的地震资料处理提供借鉴。 相似文献
16.
盆地动力学与能源资源——世纪之交的回顾与展望 总被引：26，自引：4，他引：22
沉积盆地是人类最重要的资源宝库。当今人类社会正面临环境、资源与灾害问题的严峻挑战 ,要获得对人类社会繁荣发展至关重要的能源资源就需要更深入地研究盆地。盆地动力学是当今沉积盆地理论研究领域的主要趋向。为了认识盆地的成因及演化过程中的一系列特征 ,不仅需要了解盆地与板块构造格架的关系 ,还需要了解其与深部地幔对流系统的关系。天然地震层析、岩浆岩石学地球化学和盆地模拟技术的综合应用提供了研究这一重要问题的手段。盆地中流体系统的研究对油气成藏和层控金属矿床成矿以及对地下水资源的利用和保护具有关键意义 ,以往研究薄弱的这一领域将成为多学科研究的聚焦点。盆地及其中的油气、煤和放射性矿产等能源资源研究和勘探事业的发展一直有赖于高技术手段、高精度的地球物理技术 ,如三维、四维和多波地震探测 ,以及计算机模拟技术。在新世纪之初将更精确地提供地下地质体和流体活动的影像。计算机模拟技术将成为研究地质与成藏过程的不可缺少的手段。应用新理论和新技术重新观察和审视沉积盆地的内部构成将带来资源勘查的更大发展 相似文献
17.
中国东部中、新生代含油气盆地火成岩油气藏成藏机制 总被引：17，自引：1，他引：16
中国东部中、新生代盆地油气资源丰富,其地层中广泛发育着以玄武质及粗面质为主的火成岩。这些火成岩既可为油气提供储集空间也可作为油气藏的盖层,形成了一定量与火山岩及潜火山岩相关的油气藏。与火山岩有关的油气藏主要有火山岩储层型、火山岩盖层型和风化壳型,而与潜火山岩有关的油气藏主要有拱张裂缝型、隐爆角砾岩型、原生裂缝型、蚀变破碎型和侧向隔挡型。本文评述了这些火成岩型油气藏的成藏机制,提出了中国东部中、新生代含油气盆地中的火成岩油气藏综合成藏模型,以期这类油气藏在今后的油气勘探工作中得到充分重视。 相似文献
18.
The complexity of sediment recycling as revealed by common Pb isotopes in K-feldspar 总被引：1，自引：0，他引：1
Simon P.Johnson Christopher L.Kirkland Noreen J.Evans Brad J.Mc Donald Huntly N.Cutten 《地学前缘(英文版)》2018,9(5):1515-1527
Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia. 相似文献
19.
Ambient noise analysis in Northern Taiwan revealed obvious lateral variations related to major geological units. The empirical Green’s functions extracted from interstation ambient noise were regarded as Rayleigh waves, from which we analyzed the group velocities for period from 3 to 6 s. According to geological features, we divided Northern Taiwan into seven subregions, for which regionalized group velocities were derived by using the pure-path method. On average, the group velocities in mountain areas were higher than those in the plain areas. We subsequently inverted the S-wave velocity structure for each subregion down to 6 km in depth. Following the analysis, we proposed the first models of geology-dependent shallow S-wave structures in Northern Taiwan. Overall, the velocity increased substantially from west to east; specifically, the mountain areas, composed of metamorphic rocks, exhibited higher velocities than did the coastal plain and basin, which consist of soft sediment. At a shallow depth, the Western Coastal Plain, Taipei Basin, and Ilan Plain displayed a larger velocity gradient than did other regions. At the top 3 km of the model, the average velocity gradient was 0.39 km/s per km for the Western Coastal Plain and 0.15 km/s per km for the Central Range. These S-wave velocity models with large velocity gradients caused the seismic waves to become trapped easily in strata and, thus, the ground motion was amplified. The regionalized S-wave velocity models derived from ambient noises can provide useful information regarding seismic wave propagation and for assessing seismic hazards in Northern Taiwan. 相似文献
20.
Modal analysis, bulk-rock geochemistry and phase chemistry of sandstones of the Miocene Fat'ha and Injana formations, northern Iraq, show that the clastics were derived from heterogeneous sources that include basic igneous and metamorphic rocks as well as older sedimentary rocks. The sandstones are generally carbonate-rich lithic arenites. Their geochemistry supports the petrographic results and indicates that they are all Fe-rich, lithic or quartz arkosic sandstones. According to geochemical data, garnets are derived from metamorphic sources, hornblende is of igneous origin, and clinopyroxenes, are produced by basic igneous rocks. Epidote is most probably to be a product of disintegration of metamorphic rocks, essentially, metamorphosed igneous rocks. Rutile geochemistry implies low-grade metamorphic and basic to ultrabasic igneous sources. Chemical composition of chromian spinels indicates that they are derived from Alpine-type peridotite. The ophiolitic-radiolarite belts of Taurus-Zagros as well as the uplifted Cretaceous and Paleocene strata of north and northeastern Iraq are likely to be the major source of clastics to the Fat'ha–Injana basin, a foreland basin formed as a result of the continental Arabian and Turkish/Iranian plates collision. 相似文献