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萧山-球川断裂是浙江地区1条大规模的北东向断裂,在该断裂附近曾发生过多次破坏性地震。本文通过地质调查、电法勘探和探槽开挖等方法,对萧山-球川断裂富阳—建德段第四纪活动性进行了研究。萧山-球川断裂富阳—建德段的遥感影像线性特征清楚,对地貌的控制作用较为明显,对山前的第四系发育有明显影响。通过对断裂露头剖面的分析,认为萧山-球川断裂富阳—建德段活动性质以走滑兼具逆冲为主。通过本次开挖的富阳峙山村探槽,结合ESR年龄测定,判定该断裂在第四纪早、中期有过活动,但未断错上覆中更新统上部地层,其最新活动时代为早、中更新世。 相似文献
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板岩作为一种浅变质岩在我国有着广泛的分布,对其地震波速度的研究将有助于对这类过渡性岩石的有效区分,对于浅层地壳的各向异性研究也具有重要意义.本文对采自云南丙中洛地区的板岩样品进行了地震波速度的室内实验研究,其中部分实验是在加拿大Dalhousie High Pressure Laboratory完成.实验获得了板岩在围压10~600 MPa条件下、不同构造主方向（X,Y和Z）上的地震波速度,在围压600 MPa时,X、Y、Z三个方向的P波速度分别为6.58、6.46、5.91 km/s,平均速度为6.30 km/s,S波平均速度约为3.62 km/s,VP/VS=1.74;并初步分析了板岩地震波速度、横波分裂及其波速各向异性随着围压的变化规律,发现所测量的板岩在较低围压（<150 MPa）时波速的各向异性随围压升高而迅速减小,主要是由于其内部微裂隙的定向排列引起的,而随着围压的继续增加（>150 MPa时）微裂隙基本闭合,黑云母、阳起石等片状矿物的定向排列成为其地震波各向异性的主导诱因,此时（围压为600 MPa）VP、VS的各向异性分别稳定在13%、16%左右.本研究所获取的基础实验数据及所探讨的板岩地震波性质将为确定地壳上部显微裂隙的优选定向、浅层地壳的各向异性分析、地球物理模型条件约束等提供基础. 相似文献
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本文在理论上研究了对齐误差对测试地震计自噪声的影响。指出对齐误差影响到2台仪器记录间的计算互功率谱密度, 进而影响到被测仪器记录间相干函数计算, 最终影响到被测仪器的自噪声计算。发现当存在对齐误差时, 在信噪比较高频段计算得到的自噪声水平比仪器的实际自噪声水平要高, 在一般的实际测试中可能高20 dB以上。为了消除对齐误差对自噪声测试的影响, 提出通过投影逆变换把观测记录变换到标准坐标系下, 再用变换后的观测记录来计算地震计自噪声。给出了基于以上思路和传感参数对比测试方法的地震计自噪声计算处理流程, 合成数据、 实际测试数据的处理检验计算结果表明, 本文方法可以有效克服地震计自噪声测试中对齐误差的影响。 相似文献
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目的:分析淋巴结结核的CT和MRI表现特点,并与病理学对照,探讨两种检查方法的应用价值。方法:回顾性分析2010年1月至2014年12月间34例经手术、穿刺病理或临床证实为淋巴结结核患者的CT或MRI影像学资料,分别从生长方式（融合/非融合）、边缘（光滑/欠光滑）、境界（清晰/欠清晰）、密度及信号、增强后强化方式（均匀/不均匀/环形规则/环形不规则）这5个方面对所受累淋巴结进行分析。结果:34例患者中共累及223枚淋巴结,其中颈部淋巴结67.7%,纵隔内淋巴结27.7%,肺门淋巴1.8%,肺内淋巴结0.5%,腹腔淋巴结0.5%,腹膜后淋巴结1.8%。所有受累淋巴结中,8.5%呈融合性生长,83.9%形态规则,79.4%边缘光滑。CT上发现的171枚病变淋巴结以等密度较多（53.8%）、低密度次之（43.3%）,MRI上发现的66枚病变淋巴结中98.5%为等T1长T2信号。所有CT及MRI观察到的病变淋巴结中,除57%的病灶密度或信号均匀外,仅伴钙化的为12.6%,仅伴部分坏死的26.9%,另外有3.6%同时伴钙化及坏死;增强扫描的204个病变淋巴结中,1%钙化显著、未见明显强化,38.7%均匀强化,伴坏死者内见不强化的低密度区,11.3%呈环形规则强化（均位于颈部）,8.3%环形不规则强化（纵隔内82.4%）,5.9%可见病变淋巴结内有分隔样强化（均位于颈部）。结论:CT与MRI对于淋巴结结核具有重要诊断价值,两者均能清晰显示病变部位、形态以及边缘情况,MRI对于病变边缘及周围情况显示较CT更明确,尤其是增强后,对于包膜及邻近组织受累情况的显示也更加敏感。 相似文献
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Mostafa Baniasadi Mohammad Reza Zare' Mehrjordi Hossein Mehrabi Boshrabadi Hamid Reza Mirzaei Khalilabad Abbas Rezaei Estakhrooye 《Ground water》2020,58(4):560-570
In recent decades, increased extraction of groundwater for human and agriculture consumption has led to a substantial drop in groundwater level in large areas of across the world. Declining groundwater levels is a serious problem in itself and has multiple economic, social, cultural, political, security-related, and environmental externalities. The negative economic-environmental externalities of overextraction of groundwater in the Orzouiyeh plain in the Kerman Province, Iran, were evaluated using methods such as replacement cost, production function, market prices, shadow price, and the value of the input marginal product. After evaluating externalities, the Positive Mathematical Programming method was used to evaluate different water policies to reduce the consumption of groundwater. The total economic losses due to the externalities were calculated to equal 2.8 U.S. million dollars. The damages caused by environmental externalities were calculated to equal 436.1 U.S. million dollars. The results related to the positive planning model show that the best policy among different options, such as deficit irrigation policy or combined policies, involves implementation of pressurized irrigation systems. 相似文献
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巢湖沉积物重金属富集特征与人为污染评价 总被引：15，自引：6，他引：9
本文分析了巢湖主要入湖河流河口区表层沉积物及西部湖心区沉积岩芯中Al、Fe、Ni、Cr、Cu、Zn、Pb、Li、V等金属元素变化特征,采用地球化学方法对金属元素变化的"粒度效应"进行矫正,并以Li、V为参照元素对矫正结果进行检验;参考历史沉积物,对河口区及西部湖心区沉积物重金属人为污染特征进行分析;结合沉积岩芯210Pb年代结果,估算西部湖心区近150a来Ni、Cr、Cu、Zn、Pb等重金属元素的人为污染贡献量.结果表明,河口表层沉积物重金属污染具有显著的空间差异,南淝河河口重金属人为污染最重,其中Ni、Cr、Cu、Zn、Pb的人为污染贡献量分别为12.2、32.2、25.3、479.9和76.0 mg/kg,分别占总含量的35%、37%、64%、92%和77%;其次是柘皋河河口,主要重金属污染元素为Cu、Zn和Pb,人为污染贡献量达57.6、57.0和19.5 mg/kg,分别占总含量的73%、47%和36%;而派河、白石山河、杭埠河等河口表层沉积物中重金属元素人为污染程度较弱.巢湖西部湖心区主要污染元素为Cu、Zn、Pb,人为污染开始于1950s,1980年以来其人为污染贡献量显著增加,平均为16.2、245.6、47.8 mg/(m2.a),分别占各元素沉积通量的23%、61%和37%;Ni人为污染开始于1980s初期,人为污染贡献量平均为12.6 mg/(m2.a),占其沉积通量的13%左右;Cr基本未受人为污染影响.西部湖心区沉积岩芯及南淝河河口表层沉积物中重金属污染程度均表现为Zn>Pb>Cu,而且南淝河河口沉积物重金属污染程度显著高于西部湖心区.结合主要入湖河流径流量与河口沉积物重金属污染特征,认为巢湖西部湖心区重金属污染主要通过南淝河输入,来自合肥等城市的废水是主要的污染源. 相似文献
8.
Aquifers of the peninsulas of Florida and northern Yucatan are Tertiary marine carbonate formations showing many lithologic and faunal similarities. In addition, the tropical to subtropical climates of the two areas are similar, each having annual rainfall of about 1000 to 1500 mm.
Despite similarities in these fundamental controls, contrasts in the hydrologic and geochemical systems are numerous and striking. For example, Florida has many rivers; Yucatan has none. Maximum thickness of fresh ground water in Florida is about 700 meters; in the Yucatan it is less than 70 meters. In Florida the gradient of the potentiometric surface averages about 1 meter per kilometer; in the Yucatan it is exceedingly low, averaging about 0.02 meter per kilometer. In Florida the chemical character of water changes systematically downgradient, owing to solution of minerals of the aquifer and corresponding increases in total dissolved solids, sulfate, calcium, and Mg-Ca ratio; in the Yucatan no downgradient change exists, and dominant processes controlling the chemical character of the water are solution of minerals and simple mixing of the fresh water and the body of salt water that underlies the peninsula at shallow depth.
Hydrologic and chemical differences are caused in part by the lower altitude of the Yucatan plain. More important, however, these differences are due to the lack of an upper confining bed in Yucatan that is hydrologically equivalent to the Hawthorn Formation of Florida. The Hawthorn cover prevents recharge and confines the artesian water except where it is punctured by sinkholes, but sands and other unconsolidated sediments fill sinkholes and cavities and impede circulation. In the Yucatan the permeability of the entire section is so enormous that rainfall immediately infiltrates to the water table and then moves laterally to discharge areas along the coasts. 相似文献
9.
We examine relationships between nationwide sparing use of water and farmer income of China in this article. As increasing implementation of water projects and irrigation system, the cost of water use has increased in many regions. However, as local policy-oriented urban expansion and ecological restoration have carried out during the past decade, water demand has increased. The spatial distributions of water use and farmer income are uneven and their relationships are ambiguous over time, especially it is uncertain that farmers can benefit from those so called water-saving programs when urban expansion grows faster in China. Based on consumption theory, empirical results of Blundell–Bond dynamic panel-data model with generalized method of moments (GMM) estimators indicate saving one percent of water has positive impacts at 0.085–0.35 percent on farmer income in the following statistical year. Population has negative impacts on farmer income. Particularly in Central China, one percent of increase in population will statistically significantly decrease 0.276 percent of contemporaneous farmer income. Particularly, in Eastern China with large population during years 2004 through 2012, the total amount of water use increases one percent, contemporaneous farmer income loses 0.04 percent. Thus, saving water can benefit future farmer income, and it indicates that urban expansion may induce the diversion of resources and agricultural production from rural to urban area. Policy implication of relationships between water allocation and farmer income distribution caused by water-saving programs needs to be further studied at regional scale, in particularly to the regions with large population and urban expansion in China. 相似文献
10.
华北平原周边北西向强震地表地震断层及全新世断裂活动特征 总被引：8，自引：0，他引：8
讨论了华北平原周边１９７５年海城地震，１９３７年荷泽地震及１８３０年磁县地震３次强震的地表地震破裂特征以及这３个地区北西向断裂的全新世活动。研究结果表明，尽管这３次强震地表破裂显示较弱，断续分布，仍反映了存在北西向地表破裂带，活动方式呈左旋走滑兼正倾滑。 相似文献
11.
H. Prez-de-Tejada 《Journal of Atmospheric and Solar》2005,67(17-18):1786
The general features of the region of interaction of the solar wind with the ionosphere of Venus and Mars are compared using data obtained with the Mariner 5 and the Pioneer Venus Orbiter (PVO) spacecraft for Venus and with the Phobos II, the Mars Global Surveyor (MGS) and the Mars Express spacecraft for Mars. Despite the overall weak intrinsic global magnetic field that is present in both planets there are significant differences in the manner in which the interplanetary magnetic field accumulates and is organized around and within their ionosphere. Such differences are unrelated to the crustal magnetic field remnants inferred from the MGS measurements around Mars. In fact, while in Venus and Mars there is a region in which the magnetic field becomes enhanced as it piles up in their plasma environment it is shown that such a region exhibits different regimes with respect to changes in the ion composition measured outside and within the ionosphere. At Venus the region of enhanced magnetic field intensity occurs in general above the ionopause which represents the boundary across which there is a change in the ion composition with dominant solar wind protons above and planetary O+ ions below. At Mars the region of enhanced magnetic field is located below a magnetic pileup boundary across which there is also a comparable change in the ion composition (solar wind protons above and planetary O+ ions below). It is argued that this difference in the relative position of the region of enhanced magnetic field with respect to that of a plasma boundary that separates different ion populations results from the peculiar response of the ionosphere of each planet to the oncoming solar wind dynamic pressure. While at Venus the peak ionospheric thermal pressure is in general sufficient to withhold the incident solar wind kinetic pressure there is a different response in Mars where the peak ionospheric thermal pressure is in general not large enough to deviate the solar wind. In this latter case the ionosphere is unable to force the solar wind to move around the ionosphere and as a result the oncoming electron population can reach low altitudes where it is influenced by neutral atmospheric particles (the solar wind proton population is replaced at the magnetic pileup boundary which marks the upper extent of the region where the interplanetary magnetic field becomes enhanced). Peculiar conditions are expected near the magnetic polar regions and over the terminator plane where the solar wind is directed along the sides of the planet. 相似文献
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The strongly deformed eclogites are well developed in ultra-high pressure jadeite-quartzite zone of the Dabie Mountains, Eastern
China, and garnets had been deformed strongly. Observations by transmission electron microscopy identified not only structure
of plastic deformation occurring as free dislocation, dislocation loops and dislocation walls, but also clusters of water
molecules present in the deformed garnet. Using infrared spectroscopy, two types of hydrous components are identified as the
hydroxyl and free-water in the garnet. Based on analysis of microstructure mechanism of deformation in garnets, and experimental
data of petrology, the clusters of water molecules were considered to lead strong plastic deformation of garnet by dislocations
because of mechanical weakening. 相似文献
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目的：通过ＣＴ、Ｂ超对胆囊壁形态改变的观察,探讨其在腹水的签别中的诊断价值。方法：回顾性分析６０例腹水患者胆囊壁的形态改变,发现胆囊壁的形态与腹水的性质有关。结论：ＣＴ、Ｂ超对腹水患者的胆囊壁形态的观察,有助于腹水性质的签别,并对腹水病因的寻找或断定均有一定的指导意义。 相似文献
15.
The degree and distribution of damage to buildings subjected to earthquakes is a concern of the Chinese Government and the public.Seismic damage data indicates that seismic capacities of different types of building structures in various regions throughout mainland of China are different.Furthermore,the seismic capacities of the same type of structure in different regions may vary.The contributions of this research are summarized as follows:1)Vulnerability matrices and earthquake damage matrices of masonry structures in mainland of China were chosen as research samples.The aim was to analyze the differences in seismic capacities of sample matrices and to present general rules for categorizing seismic resistance.2)Curves relating the percentage of damaged masonry structures with different seismic resistances subjected to seismic demand in different regions of seismic intensity(VI to X)have been developed.3)A method has been proposed to build vulnerability matrices of masonry structures.The damage ratio for masonry structures under high-intensity events such as the Ms 6.1 Panzhihua earthquake in Sichuan province on 30 August2008,was calculated to verify the applicability of this method.This research offers a significant theoretical basis for predicting seismic damage and direct loss assessment of groups of buildings,as well as for earthquake disaster insurance. 相似文献
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Yu. O. Kuzmin 《Izvestiya Physics of the Solid Earth》2013,49(5):626-642
The results of analyzing the long (20–50 years) time series of geodetic observations carried out in the regions with enhanced seismotectonic activity (Kopet Dag, Kamchatka, and California) are presented. It is established that recent vertical and horizontal displacements in the fault zones estimated by instrumental geodetic observations with increased spatiotemporal resolution indicate that the deformations in the fault zones paradoxically deviate from the movements inherited from the previous geological epochs. The paradoxes of high and low deformation rates in recent geodynamics lie in the reliably established empirical fact that extremely high local deformation rates (up to 10?5 per annum and higher) exist in the fault zones in the setting of weak regional deformations, whose annual rates are by two to three orders of magnitude lower. Very low annual average rates of relative horizontal deformations, which only measure 3–5 amplitudes of tidal deformations of the solid Earth, are revealed in the seismically active regions of Kopet Dag and Kamchatka as well as in the San Andreas Fault Zone in northern California. The fault-block dilemma arising in the interpretation of the observations of recent fault geodynamics is formulated. Either the role of active element, which forms the present anomalous deformations, is played by a block, while a fault plays the role of the passive element, or the fault zone itself is a source of anomalous movements, while the blocks are passive elements (hosting medium). It is shown that paradoxes of low and high deformation rates vanish if we assume that the recent anomalous geodynamics is formed by parametric excitation of the deformation processes in the fault zones in the conditions of quasi-static loading. 相似文献
18.
Investigation of mechanisms of formation of biphenyls and benzonaphthothiophenes by simulation experiment 总被引：1，自引：0，他引：1
The formation mechanisms of biphenyl series and benzonaphthothiophene series are investigated by means of simulation experiment. Biphenyl series are likely formed in two ways: one is the aromatization of the chain compounds containing conjugated C== C double bonds or the compounds with such a kind of sidechains, and the other is the reaction of sulfur with ordinary chain compounds, in which sulphur acts on ordinary sidechain compounds by seizing some hydrogens and forming (H2S and) the intermediates with conjugated C== C double bonds first, and then the intermediates are aromatized. One of the basic precursors of benzonaphthothiophenes is likely the phenylnaphthalenes which may originate from the chain compounds containing conjugated C== C double bonds, the compounds with such sidechains and saturate or unsaturate chain compounds. Thermal stability of biphenyls is high, but they can become dibenzothiophenes and polycyclic aromatic hydrocarbons or dibenzofurans and polycyclic aromatic hydrocarbons respectively in the presence of sulphur or oxygen. The ratio of biphenyl and m-biphenyl to biphenyls may be employed to indicate the depositional environment in the mild to medium maturation, of which the higher value indicates a fresh water depositional environment and the lower indicates a saline depositional environment. The relative high content of benzonaphthothiophenes in the crude oil indicates that the crude oil has undergone an intense sulfurization in the source rock or reservoir. 相似文献
19.
A. N. Morozov N. V. Vaganova V. E. Asming Ya. A. Mikhailova 《Izvestiya Physics of the Solid Earth》2018,54(2):292-309
The hypocenters of the earthquakes recorded in the north of the Russian Plate from 1982 to 2013 are relocated. The relocation of the hypocenters is based on the common velocity section, common methodology, and the entire set of the initial data and bulletins available from the Russian and foreign seismic stations. The efficiency of the algorithm for calculating the hypocentral parameters and the velocity section is demonstrated by the example of two nonmilitary nuclear explosions in July 18, 1985 and September 6, 1988 in the northern part of the European Russia. For the first time, two earthquakes of July 19, 1982 and October 7, 2012, which have not been previously reported in the catalogs for the north of the Russian plate, are included in the seismic catalog. 相似文献
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核磁共振测井在火成岩地层应用的适应性分析 总被引：1，自引：0，他引：1
火成岩岩石具有高磁化率特征,与沉积岩差别明显,岩石的高磁化率会对核磁共振信号产生显著影响,开展核磁共振测井在火成岩地层应用的适应性分析研究,为广泛使用核磁共振测井用于火成岩储层评价提供参考.采用理论模拟、实验分析及实际测井资料相结合的方法,分析了高磁化率岩石的核磁共振响应特征.分析结果表明,火成岩岩石具有很高的磁化率,从酸性火成岩到基性火城岩,岩石的磁化率一般是逐渐增大的.高磁化率岩石孔隙内部会产生强梯度磁场,孔隙内部的磁场梯度越强,核磁共振的T2谱前移越明显,核磁信号衰减幅度也越大,核磁分析孔隙度与常规分析的孔隙度误差也越大;相同岩石磁化率情况下,岩石孔径越小,岩石孔隙内部磁场梯度越强,核磁信号衰减越大,核磁共振测井计算的孔隙度也越低.因此,核磁共振测井与岩性有关系,核磁共振测井会受到高磁化率岩石的显著影响.核磁共振测井在部分火成岩,尤其在中基性火成岩和小孔径火成岩储层中应用具有很大的局限性. 相似文献