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福建沿海的海面变化及其影响 总被引：6，自引：0，他引：6
本文根据福建沿海４个验潮站的验潮资料，计算了各站的局域海平面长趋势变化。结果表明，福建沿海的局域海平面变化速率为１￣２ｍｍ／ａ，４个验潮站的平均变化速率为０．９ｍｍ／ａ，最后讨论了海面变化可能引起的次生灾害。 相似文献
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祁连山西段酒西盆地区阶地构造变形的研究 总被引：25，自引：3，他引：22
对祁连山西段酒西盆地晚第四纪阶地的研究表明,该区早第四纪以挤压褶皱、逆冲为特征的构造变形在晚更新世期间乃至全新世仍继承性地进行着,表现为横穿褶皱和逆断裂带的河流及冲沟阶地面的形成、阶地类型的转变、阶地级数的增多和阶地面被断错或发生拱曲变形．其中祁连山北缘大断裂晚更新世晚期以来的垂直运动速率约为１．９２～２．００ｍｍ／ａ．老君庙背斜逆断裂带在晚更新世初以来的垂直运动速率约为１．１５～２．５６ｍｍ／ａ．白杨河背斜逆断裂带晚更新世初以来的垂直运动速率约为０．３２～０．５８ｍｍ／ａ． 相似文献
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太白维山山前断裂活动特征的初步研究 总被引：1，自引：0，他引：1
本文立足于大量的野外第一手资料，综合解剖了太白维山山前断裂的几何结构，并就其运动学特征进行了初步探讨。认为：太白维山山前断裂第四纪以来的活动表现为正断型，其几何结构和运动特征都有着相同的分段性。我们将其划分为三段，西段结构简单，晚更新世以来无明显活动；中段结构复杂，一直强烈活动；东段活动强度较低。晚更新世晚期以来断裂（中段）的平均滑动速率０．４ｍｍ／ａ，全新世以来达到０．６７ｍｍ／ａ，而且这种速率 相似文献
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甘孜－玉树断裂带的晚第四纪活动特征 总被引：17，自引：1，他引：17
在航、卫片解译的基础上，结合已有的区域地质填图成果，经过详细的野外观测研究，明确了甘孜－玉树断裂带最新地表活动形迹的空间展布特征。通过对断错地貌及新地层变形与位错的研究，结合（１４）Ｃ和热释光（ＴＬ）测龄结果，对断裂带晚第四纪以来的平均滑动速率进行了初步研究。结果表明，甘孜－玉树断裂带的平均滑动速率为：甘孜段水平滑动速率为３．４±０．３ｍｍ／ａ，垂直滑动速率为２．２±０．１ｍｍ／ａ；马尼干戈段水平滑动速率为７±０．７ｍｍ／ａ；邓柯段为７．２±１．２ｍｍ／ａ；当江段为７．３±０．６ｍｍ／ａ。 相似文献
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由滨海相沉积样品反映的东南沿海海岸升降速率 总被引：1，自引：0，他引：1
收集了闽、粤、桂、琼4省（区）海岸带的^14C测年自45000aB.P.以来共490个演海相样品，依据文献[1]广东中山石歧45000aB.P，以来的渐进上升水动型海平面变化曲线，计算了相应地区晚更新世及全新世以来海岸地壳的升降速率，结果表明，除粤西和粤东一些地区及海南省外，东南沿海海岸部份地壳的升降速率，结果且明，除粤西和粤东一些地区及海南省外，东南沿海海岸份地区晚更新世及全新世时期和中期地壳主要表现为下沉，全新世中晚期特别是晚期主要反映为上升，珠江三角洲晚更新世中晚期以来主要表现为继承性下沉，现代地壳形孪测量反映的地壳升降较多地区与一述趋向大致相似，广东惠来县东60km下新礁海域及珠江三角洲灯笼沙等15个地区，是地壳升降异常速率较高地区。 相似文献
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通过实地考察、槽探和浅层地震探测等手段以及对地质构造和地下水超采环境的分析，详细地研究了大同铁路分局地裂缝带的三维构造特征，指出现今处于发展中的地裂缝带是由东向西扩展的，扩展速率为２６０～５２０ｍ／ａ，地裂缝带两侧的差异升降运动速率达２２．１～２４．４ｍｍ／ａ，主地裂缝带的水平拉张速率约１．１１～１１．６ｍｍ／ａ，垂直错动速率０．２～８．５７ｍｍ／ａ，左旋错动速率１．８７～３．５７ｍｍ／ａ。地裂缝带的活动方式为无震蠕滑型，扩展中的地裂缝是一种无震的地质灾害 相似文献
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A non-linear two-dimensional vertically stratified cross-sectional model of a constant depth basin without rotation is used
to investigate the influence of vertical and horizontal diffusion upon the wind-driven circulation in the basin and the associated
temperature field. The influence of horizontal grid resolution, in particular the application of an irregular grid with high
resolution in the coastal boundary layer is examined. The calculations show that the initial response to a wind impulse is
downwelling at the downwind end of the basin with upwelling and convective mixing at the opposite end. Results from a two-layer
analytical model show that the initial response is the excitation of an infinite number of internal seiche modes in order
to represent the initial response which is confined to a narrow near coastal region. As time progresses, at the downwind end
of the basin a density front propagates away from the boundary, with the intensity of its horizontal gradient and associated
vertical velocity determined by both horizontal and vertical viscosity values. Calculations demonstrate the importance of
high horizontal grid resolution in resolving this density gradient together with an accurate density advection scheme. The
application of an irregular grid in the horizontal with high grid resolution in the nearshore region enables the initial response
to be accurately reproduced although physically unrealistic short waves appear as the frontal region propagates onto the coarser
grid. Parameterization of horizontal viscosity using a Smagorinsky-type formulation acts as a selective grid size-dependent
filter, and removes the short-wave problem although enhanced smoothing can occur if the scaling coefficient in the formulation
is too large. Calculations clearly show the advantages of using an irregular grid but also the importance of using a grid
size-dependent filter to avoid numerical problems. 相似文献
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Nathan Paldor 《地球物理与天体物理流体动力学》2013,107(3-4):217-228
Abstract The stability of a single layer, geostrophic front of zero potential vorticity bounded by a vertical coast (wall) is investigated by means of a Rayleigh integral. It is proved that the flow of the density-driven current is stable at all wavenumbers provided the mean velocity of basic flow exceeds fL (where f is the Coriolis parameter and L is the distance between the wall and the free streamline). The frequency of the stable long waves is either zero or super-inertial. 相似文献
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Granitic coastal geomorphology: applying integrated terrestrial and bathymetric LiDAR with multibeam sonar to examine coastal landscape evolution 
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下载免费PDF全文 Coasts composed of resistant lithologies such as granite are generally highly resistant to erosion. They tend to evolve over multiple sea level cycles with highstands acting to remove subaerially weathered material. This often results in a landscape dominated by plunging cliffs with shore platforms rarely occurring. The long‐term evolution of these landforms means that throughout the Quaternary these coasts have been variably exposed to different sea level elevations which means erosion may have been concentrated at different elevations from today. Investigations of the submarine landscape of granitic coasts have however been hindered by an inability to accurately image the nearshore morphology. Only with the advent of multibeam sonar and aerial laser surveying can topographic data now be seamlessly collected from above and below sea level. This study tests the utility of these techniques and finds that very accurate measurements can be made of the nearshore thereby allowing researchers to study the submarine profile with the same accuracy as the subaerial profile. From a combination of terrestrial and marine LiDAR data with multibeam sonar data, it is found that the morphology of granite domes is virtually unaffected by erosion at sea level. It appears that evolution of these landscapes on the coast is a very slow process with modern sea level acting only to remove subaerially weathered debris. The size and orientation of the joints determines the erosional potential of the granite. Where joints are densely spaced (<2 m apart) or the bedrock is highly weathered can semi‐horizontal surfaces form. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献