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简要回顾了水文测验发展的过程,介绍了中国测验工作的现状,总结了近二十余年水文测验业务建设的重大举措,评价了水文测验技术应用成果,指出了当前中国水文测验存在的主要问题和面临的挑战,提出了今后水文测验工作发展的具体建议。 相似文献
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介绍了人工神经网络的工作原理，分析了传统专家系统的局限性，阐述了神经网络专家系统的基本构成，设计了金刚石钻头配方设计专家系统的框架，论述了该系统所采用的神经学习算法和理机制，并给出了实际应用示例。 相似文献
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寿冀平 《中国地质灾害与防治学报》1998,9(3):90-93
本文简要介绍了山东省的地层分布特点,对采空塌陷和岩溶塌陷的发生,发展过程进行了全面介绍,对产生塌陷的原因进行了分析。根据山东具体情况,确定了影响岩溶塌陷的主导因素,采用打分法进行了分区评价,对岩溶塌陷的发展趋势进行了预测,提出了防治岩溶塌陷灾害的具体措施。 相似文献
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通过辽西某厂泥石流灾害的实地调查,阐述了泥石流发生的条件,介绍了泥石流危害,分析了泥石流的现状并预测了发展趋势,提出了防治措施。 相似文献
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Evidence for partial melting along subgrain boundaries in quartz and plagioclase is documented for rocks from the Lost Creek Gneiss of the Llano Uplift, central Texas, the Wet Mountains of central Colorado, and the Albany-Fraser Orogen, southwestern Australia. Domains of quartz or plagioclase crystals along subgrain boundaries are preferentially involved in partial melting over unstrained domains of these minerals. Material along subgrain boundaries in quartz and plagioclase has the same morphology as melt pseudomorphs present along grain boundaries and is commonly laterally continuous with this former grain boundary melt, indicating the material along subgrain boundaries can also be categorized as a melt pseudomorph. Subgrain boundaries consist of arrays of dislocations within a crystal lattice, and unlike fractures would not act as conduits for melt migration. Instead, the presence of former melt along subgrain boundaries requires that partial melting occurred in these locations because it is kinetically more favorable for melting reactions to occur there. Preferential melting in high strain locations may be attributed to strain energy, which provides a minor energetic contribution to the reaction and leads to preferential melting in locations with weakened bonds, and/or the presence of small quantities of water associated with dislocations, which may enhance diffusion rates or locally lower the temperature needed for partial melting. 相似文献
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The role of pressure as a source of gravity in general relativity is considered. In homogeneous, anisotropic cosmological models, the anisotropic pressure components along different coordinate axes are included as terms in the equations determining the accelerations along these axes; in this sense, this situation is similar to how the mass density is included in these equations. A change in the pressure component along one of the coordinates leads to an anisotropic change in the accelerations along all three coordinates. However, the pressure components are not present in the equation determining the initial conditions. On the other hand, with an inhomogeneous matter density distribution, the mass density and pressure play fundamentally different roles as sources of gravity. The consequences of this are considered. 相似文献
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青藏高原新生代地壳变形对同碰撞岩浆侵位的制约 总被引：1，自引：0，他引：1
同碰撞岩浆作用是青藏高原新生代构造-岩浆活动的一种重要形式，各种类型岩浆岩广泛分布于高原内不同的构造单元中，其中有的来自地幔，不过规模都不大，它们是如何穿过异常厚的地壳侵位到近地表或喷出地表，这还是个未解之谜。根据构造分析，这些岩浆岩均侵位于新生代向斜构造中，例如侵入于高原东南边缘的楚雄复向斜、兰坪．思茅复向斜和老君山向斜的碱性岩，侵入于高原南缘的北喜马拉雅拉轨岗日向斜的片麻状花岗岩以及喷出于高原北部巴颜喀拉和雁石坪复向斜的安山-玄武岩。文中通过一个力学模式，说明这些岩浆岩的侵位受控于地壳应力场特征，即：向斜构造的下部承受的是张应力，地壳发生减薄和张裂，下地壳或上地幔熔融物质以此为通道发生向上的侵位。不过，因向斜顶部地壳承受的是挤压应力，地壳发生挤压缩短，所以只有少量岩浆能侵位到近地表并发生变形。与此相反，背斜构造的下部地壳产生的是挤压应力，阻止了下伏地壳内岩浆的侵入。因此，岩浆的侵位一般不会沿背斜发生。这一力学机制解释了为什么青藏高原规模很小的同碰撞岩浆能穿过异常厚的地壳沿一系列向斜构造侵位到近地表或喷出地表的原因。 相似文献
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Over the last four hundred years the spatial variation of intra-plate seismicity in Southwest Japan correlates well with the occurrence of great inter-plate earthquakes. For fifty years before an inter-plate earthquake the intra-plate seismic activity is highest along a belt inland. For ten years afterwards it falls off in this belt, but rises on both sides along the Philippine Sea and Japan Sea coasts. Then it becomes low and remains low throughout the whole region until fifty to thirty years before the next inter-plate event, as shown by Utsu in 1974. An intermittent underthrusting drag exerted by the Philippine Sea plate seems to control the intra-plate seismicity, which partly takes up the relative plate motion as internal deformation. When a great inter-plate earthquake occurs, tectonic stress is released and seismic activity falls off in the central belt. The breaking of the plate boundary temporarily weakens the coupling between the two plates along the shallower part of the interface, which gently dips toward the Japan Sea coast. The decoupling causes stress concentration in the deeper part and results in increased seismic activity along the Japan Sea coast. The activity along the Philippine Sea coast may be interpreted as aftershock activity. 相似文献
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扩建城市垃圾填埋场的地震稳定性分析 总被引：1，自引：0，他引：1
结合现场剪切波速试验、室内常规及动三轴试验结果,给出了扩建城市垃圾填埋场地震稳定性的有限元分析方法,并分析了扩建垃圾填埋体沿填埋体内部圆弧滑动面、新老填埋体交界面及底部和背部衬垫系统的地震稳定性。当填埋场中渗滤液水头较低时,扩建填埋体最易发生沿新老填埋体交界面的滑动。与总应力法计算结果相比较发现,总应力法只适合分析输入地震动较小的情况,而当输入地震动较大时,由于它不能考虑动孔压上升所导致的MSW软化而使得其计算的扩建填埋体沿圆弧滑动面的安全系数偏保守。另外,采用Newmark法分析了不同输入地震动时不同横、竖向扩建方案的永久位移,分析表明：扩建填埋体沿新老填埋体交界面的地震永久位移的对数近似与屈服加速度同最大水平加速度的比值呈线性关系,并给出了其永久位移的拟合公式。 相似文献
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Surface deformations on the western flank of Mt Etna volcano, spanning 1980–2004, have been analysed as they pertain to stress interactions between magma intrusions within the shallow crust along the S–SE Rift and faulting sensitivity. During this period, an accurate analysis of strain parameters, computed by inversion of SW electro‐optical distance data, suggested that the observed strong displacements on this flank of the edifice can also be related to dextral shear movements along a roughly NE–SW buried fault crossing the area covered by this network, as supported by seismic observations of the 20–24 April 2001 swarm. Moreover, Coulomb stress change model analysis confirms that the displacement along this fault, heralding the July–August 2001 eruption 2 months earlier can be related to major stresses applied by a dike intrusion at depth along the S–SE Rift, as testified by the microseismicity occurring between November 2000 and 19 April 2001. 相似文献
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辽东湾北部地区走滑构造特征与油气富集规律 总被引：2，自引：2，他引：2
辽东湾北部地区右行走滑构造特征较为典型,主要表现为:沿走滑断裂带发育雁行式伸展断裂;剖面上发育花状构造;走滑断裂沿走向呈“S”型或反“S”型波状弯曲;沿走滑断裂带断槽与断鼻构造相间分布。分析认为,渐新世晚期,辽东湾北部地区南北向拉张、东西向挤压的区域应力场控制了右行走滑构造的形成,断槽与断鼻构造相间分布是由于沿走滑断裂带局部应力场性质发生改变所致。右行走滑断裂的“S”型弯曲部位为增压弯部位,走滑断裂两侧断块在此汇聚,地层因应力集中而形成断鼻构造;右行走滑断裂的反“S”型弯曲部位为释拉张部位,走滑断裂两侧断块在此离散,地层因拉张而发生断陷形成断槽。受走滑构造所控制,油气沿走滑断层自断槽向断鼻方向运移、聚集而成藏。研究走滑构造发育特征,对于预测圈闭分布以和研究油气富集规律具有重要意义。 相似文献
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Nisha Radhakrishnan 《Journal of the Geological Society of India》2011,77(4):360-366
A broad overview of how GPS can be used to identify the active fault plane along which earthquakes occur in the seismic prone
Western Maharashtra Peninsular shield of India is given. Indian Institute of Technology, Bombay in collaboration with Indian
Institute of Geomagnetism, Mumbai was actively working in the field of crustal deformation monitoring along Western Maharashtra
from year 2004–2006. A regional GPS network had been established for this purpose, periodically observed between May 2004
to May 2006, and analysed. To understand the pattern of seismicity along Western Maharashtra region, the GPS-estimated coordinates
and displacements were used as an indicator to estimate and identify regions of high strain rates, the reliability of which
was confirmed with real seismic data collected. These strain rates were used as a means to identify the fault plane along
which the earthquakes occurred during the period of observation. 相似文献
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本文在区域地质填图的基础上,通过详细的中型构造研究和区域地质特征分析,确立了研究区的冲断推覆构造格局,讨论了浅层次冲断层带内部的构造几何学特征及冲断推覆构造运动学问题。本区晚燕山期由北向南的冲断推覆作用,控制了区内地层与岩浆岩带的展布,导致了变质相带的缺失和变质梯度的倒置,并造成了上百公里的上部地壳缩短。研究表明,纵向的区域性高角度断裂（商－丹断裂）不是重要的大地构造单元分界线。 相似文献
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Twenty three bathymetric profiles up to a depth of 28 m were surveyed along and across the western inner shelf off the Nile delta. These surveys were conducted during 1919/22, 1976/77 and 1986. Comparison of these profiles establish that there are significant delta-wide changes in the patterns of erosion and accretion that correspond to sediment movement resulting from the prevailing dynamic factors affecting this area. Maximum bottom erosion (negative relief deformation) was detected along Abu Quir bay, on the tip of the Rosetta promontory, along both sides of the Rosetta mouth, and along the Burullus-Baltim coast. In contrast, there has been maximum bottom accretion (positive relief deformation) at Abu Quir cape and at Abu Khashaba. The sources of the accreted sediment probably come from areas of beach erosion as well as from offshore due to the combined effect of the offshore-onshore exchange. 相似文献