堤防隐患探测实例分析   总被引：2，自引：0，他引：2  

石念增  刘康和 《地质灾害与环境保护》2005,16(4):376-382

在堤防隐患探测中，采用地质雷达、高密度电法、电测深法、地震折射波法等综合物探技术，并结合少量的土工试验资料，提高了物探成果的可靠性和实用性，取得了良好的应用效果．为堤防隐患探测提供了新的思路。  相似文献   

湘南多金属矿集区的圈定及深大断裂构造在成矿中的控制作用     

唐朝永  张南锋  周兴良  刘利生 《矿产与地质》2007,21(5):538-541

湘南多金属矿集区是一个世界级的多金属矿集区，包含有三条有色多金属亚成矿带。其成矿活动与深大断裂带关系密切，深大断裂为深部成矿物质提供了构造通道条件，控制了矿集区内多金属亚成矿带的形成和分布，深大断裂的交汇部位则控制了大型、超大型矿床（田）的产出。  相似文献   

大井铜-锡多金属矿床地质特征及其成因     

张信 《矿产与地质》2007,21(4):415-420

通过对大井铜-锡多金属矿床成矿地质环境、矿床地质特征以及对岩（矿）石同位素、稀土元素、成矿温度等地球化学和成矿物理化学环境的研究,认为,大井铜-锡多金属矿床为一典型的岩浆热液充填型矿床。与成矿有关的隐伏岩体受深部隐伏的深大断裂控制,可能与黄岗梁矽卡型铁-锡矿床同属一构造岩浆成矿带上不同成矿环境下形成的矿床。并认为,在该成矿带上及大井矿区深部仍有较大的找矿潜力。  相似文献   

Evidence for an active fault below the northwestern Alpine foreland of Switzerland   总被引：2，自引：0，他引：2  

U. Kastrup  N. Deichmann  A. Fröhlich  D. Giardini 《Geophysical Journal International》2007,169(3):1273-1288

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Monitoring overburden layer changes and fault movements from time-lapse seismic data on the Valhall Field     

Thomas Røste  Martin Landrø  Paul Hatchell 《Geophysical Journal International》2007,170(3):1100-1118

A method developed by Røste et al. , which discriminates between layer thickness and velocity changes, is tested on pre-stack time-lapse seismic ocean bottom cable (OBC) data from the Valhall Field. A key parameter in this discrimination process is the dilation factor, α, which is the relative velocity change divided by the relative thickness change within a given layer. The high quality and good repeatability of the OBC data enables us to estimate α with a reasonable accuracy for α-values between 0 and −5. For α-values below −5, complementary information, like for instance geomechanics is required. For the top reservoir horizon we estimate a maximum subsidence of 0.50 m ± 0.29 m and a corresponding velocity decrease for the sequence from the seabed to the top reservoir of 2.0 m s⁻¹± 0.40 m s⁻¹.
Time-lapse distortion patterns with characteristic time-shift versus offset signatures are observed. The positions and vertical extents of the distortion zones are determined from ray path considerations and modelling. The distortion zones correlate with buried faults, indicating that a (time-lapse) distortion zone might be produced by a localized slip in a fault zone. We present an extended method which allows for vertical (in addition to lateral) variations in the relative thickness and velocity changes. This method can be viewed as a simplified version of time-lapse tomography, but involving fewer unknown parameters, giving more stability to the estimated changes in thickness and velocity. Using this technique, we are able to estimate α for positions with localized time-lapse distortions.  相似文献   

雷达图像中的转换构造信息及其应用     

石火生  林珲  王长林 《遥感学报》2002,6(6):517-522

低序次断裂是地壳变形的直接产物，具有丰富的构造变形信息，经过转换的低序次构造。形式多样，图案复杂，是构造研究的重要对象，也是地表稳定性研究的重要基础。利用香港地区航空雷达图像资料，提取其中低序次构造的弱信息，建立转换变形模型，以分析区内不稳定地表的构造背景。区内北东向断裂是主要构造，其右行剪切形成一系列低序次R面，P面，R^1面构造，在雷达图像上表现为线性弱信息并且与微地貌发育有关。利用线性构造增强，提取技术和低序次构造组合分析方法，结合野外地质调查，确定马鞍山地区EW向的张性破裂是NE向张剪断裂的转换，是造成马鞍山滑坡的重要地质因素。  相似文献   

Seismic activity triggered by the 1999 Izmit earthquake and its implications for the assessment of future seismic risk   总被引：8，自引：0，他引：8  

Ali Pinar  Yoshimori Honkura  Keiko Kuge 《Geophysical Journal International》2001,146(1):F1-F7

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内蒙古白乃庙金矿断裂构造控矿研究   总被引：5，自引：1，他引：5       下载免费PDF全文

和钟铧  周立宏等 《地质与勘探》2001,37(2):28-31

白乃庙金矿由石英脉型和蚀变岩型金矿组成，并受断裂及其破碎带控制，研究了白乃庙金矿断裂构造与成矿关系，断裂构造趋势面与找矿及矿体在断裂中的富集规律，并对成矿远景进行了预测。  相似文献   

Climate induced temperature effects on growth performance, fecundity and recruitment in marine fish: developing a hypothesis for cause and effect relationships in Atlantic cod (Gadus morhua) and common eelpout (Zoarces viviparus)     

H. O. Prtner  B. Berdal  R. Blust  O. Brix  A. Colosimo  B. De Wachter  A. Giuliani  T. Johansen  T. Fischer  R. Knust  G. Lannig  G. Naevdal  A. Nedenes  G. Nyhammer  F. J. Sartoris  I. Serendero  P. Sirabella  S. Thorkildsen  M. Zakhartsev 《Continental Shelf Research》2001,21(18-19)

Effects of global warming on animal distribution and performance become visible in many marine ecosystems. The present study was designed to develop a concept for a cause and effect understanding with respect to temperature changes and to explain ecological findings based on physiological processes. The concept is based on a wide comparison of invertebrate and fish species with a special focus on recent data obtained in two model species of fish. These fish species are both characterized by northern and southern distribution limits in the North Atlantic: eelpout (Zoarces viviparus), as a typical non-migrating inhabitant of the coastal zone and the cod (Gadus morhua), as a typical inhabitant of the continental shelf with a high importance for fisheries.Mathematical modelling demonstrates a clear significant correlation between climate induced temperature fluctuations and the recruitment of cod stocks. Growth performance in cod is optimal at temperatures close to 10°C, regardless of the population investigated in a latitudinal cline. However, temperature specific growth rates decrease at higher latitudes. Also, fecundity is less in White Sea than in North and Baltic Sea cod or eelpout populations. These findings suggest that a cold-induced shift in energy budget occurs which is unfavorable for growth performance and fecundity. Thermal tolerance limits shift depending on latitude and are characterized by oxygen limitation at both low or high temperatures. Oxygen supply to tissues is optimized at low temperature by a shift in hemoglobin isoforms and oxygen binding properties to lower affinities and higher unloading potential. Protective stimulation of heat shock protein synthesis was not observed.According to a recent model of thermal tolerance the downward shift of tolerance limits during cold adaptation is associated with rising mitochondrial densities and, thus, aerobic capacity and performance in the cold, especially in eurythermal species. At the same time the costs of mitochondrial maintenance reflected by mitochondrial proton leakage should rise leaving a lower energy fraction for growth and reproduction. The preliminary conclusion can be drawn that warming will cause a northern shift of distribution limits for both species with a rise in growth performance and fecundity larger than expected from the Q₁₀ effect in the north and lower growth or even extinction of the species in the south. Such a shift may heavily affect fishing activities in the North Sea.  相似文献   

Reactivated strike–slip faults: examples from north Cornwall, UK     

Young-Seog Kim  Jim R. Andrews  David J. Sanderson   《Tectonophysics》2001,340(3-4):173-194

Several strike–slip faults at Crackington Haven, UK show evidence of right-lateral movement with tip cracks and dilatational jogs, which have been reactivated by left-lateral strike–slip movement. Evidence for reactivation includes two slickenside striae on a single fault surface, two groups of tip cracks with different orientations and very low displacement gradients or negative (left-lateral) displacements at fault tips.

Evidence for the relative age of the two strike–slip movements is (1) the first formed tip cracks associated with right-lateral slip are deformed, whereas the tip cracks formed during left-lateral slip show no deformation; (2) some of the tip cracks associated with right-lateral movement show left-lateral reactivation; and (3) left-lateral displacement is commonly recorded at the tips of dominantly right-lateral faults.

The orientation of the tip cracks to the main fault is 30–70° clockwise for right-lateral slip, and 20–40° counter-clockwise for left-lateral slip. The structure formed by this process of strike–slip reactivation is termed a “tree structure” because it is similar to a tree with branches. The angular difference between these two groups of tip cracks could be interpreted as due to different stress distribution (e.g., transtensional/transpressional, near-field or far-field stress), different fracture modes or fractures utilizing pre-existing planes of weakness.

Most of the d–x profiles have similar patterns, which show low or negative displacement at the segment fault tips. Although the d–x profiles are complicated by fault segments and reactivation, they provide clear evidence for reactivation. Profiles that experienced two opposite slip movements show various shapes depending on the amount of displacement and the slip sequence. For a larger slip followed by a smaller slip with opposite sense, the profile would be expected to record very low or reverse displacement at fault tips due to late-stage tip propagation. Whereas for a smaller slip followed by larger slip with opposite sense, the d–x profile would be flatter with no reverse displacement at the tips. Reactivation also decreases the ratio of d_max/L since for an original right-lateral fault, left lateral reactivation will reduce the net displacement (d_max) along a fault and increase the fault length (L).

Finally we compare Crackington Haven faults with these in the Atacama system of northern Chile. The Salar Grande Fault (SGF) formed as a left-lateral fault with large displacement in its central region. Later right-lateral reactivation is preserved at the fault tips and at the smaller sub-parallel Cerro Chuculay Fault. These faults resemble those seen at Crackington Haven.  相似文献