排序方式: 共有42条查询结果,搜索用时 875 毫秒
21.
Marek Grad Rolf Mjelde Wojciech Czuba Aleksander Guterch the IPY Project Group 《Geophysical Prospecting》2012,60(5):855-869
Wide‐angle seismic data acquired by use of air‐guns and ocean bottom seismometers (OBS) contain strong direct water arrivals and multiples, generally considered as noise and thus not included in the modelling. However, a recent study showed that standard ray‐tracing modelling of the water multiples recorded off the Bear Island, North Atlantic, provided a reliable estimate of the velocity distribution in the water layer. Here, we demonstrate that including the amplitudes in the modelling provide valuable information about the VP contrast at the seafloor, as well as the VP/VS ratio and attenuation (QP) of the uppermost sediments. The VP contrast at the seafloor is estimated at about 250 m/s, within a precision of approximately ±30 m/s. The VP/VS ratio in the uppermost sedimentary layer is modelled in the range 2.25–2.50 and the QP factor is estimated at 1000 for the water, 30–50 for the uppermost layer and 40–50 for the second sedimentary layer. The values obtained for the sediments suggest a lithology dominated by silty clays, with porosity below average. 相似文献
22.
康山“古油藏”讨论之三——康山“沥青脉”的成因 总被引:1,自引:0,他引:1
通过对康山固体可燃脉体产状、脉石矿物性质、构造发展史的综合分析,认为其成因很可能是下寒武统荷塘组中的软沥青和有机质,在加里东运动期间,由于区域应力体系的变化而爆炸运移形成的。康山脉石矿物是沥青和有机质,不是煤和无机物。沥青的源岩为下寒武统荷塘组富有机质的黑色泥岩、硅质泥岩、硅质岩。康山脉中的固体沥青和有机质,当初挤入时应呈塑性流动状态,康山沥青系由石油经热演化而成。 相似文献
23.
Vernon A. Phelps Research Scientist Project Director Armin W. Troesch Assistant Research Scientist John P. Hackett Graduate Research Assistant 《Ocean Engineering》1980,7(2):281-304
Fluid-flow measuring devices intended for full scale use were designed and tested. One device consisted of a rake supporting different types of pitot tubes. This will be used to obtain a velocity profile of the boundary layer of a test ship. The other device was a five-hole pitot tube that was used in a wake survey. The pressure transport medium (i.e. the medium that carried the pressure signal from the pitot tube to the pressure transducer) was air instead of water. This proved to be successful, as the results indicate. 相似文献
24.
Nic Walton AstroGrid Project Scientist 《Astronomy& Geophysics》2005,46(3):3.23-3.26
When the UK's AstroGrid went on-line in May it became the first of the world's new "virtual observatories" to go live. Nic Walton explains how it works and how it is already delivering new science. 相似文献
25.
TU Qiming Engineer Navigation Office of the Three Gorges Project Ministry of Communication 《国际泥沙研究》1991,(3)
Sedimentation problems in the access channels of the Gezhouba Navigation Locks at the Third Channel, which is of great importance for the navigation are discussed in this paper:1) the cause of deposition in the access channel, 2) effects of the deposit--reducing embankment and sediment sluices and 3) the relation between the sediment deposition at the Third Channel and the sediment discharge of the Yangtze River. Analyzing a four years' field data of sounding records with respect to the lock operation, it can be seen that the flood release through the navigation channel resulted in severe deposition, especially the sediment deposits induced by eddy current are difficult to be cleared off by flushing and jeopardize the working conditions of the lock operation. It is obvious that the flood release through the navigation channel should be minimized. In order to reduce the sediment deposits caused by eddy current attempts should be made to adjust the alignment of the boundaries and layout of the entrance of access channels. 相似文献
26.
印度板块俯冲到藏南之下的深反射证据 总被引:9,自引:1,他引:9
喜马拉雅和相邻的西藏高原,构成了地球上最大的高原和异常厚地壳的地区,是作为印度板块和亚洲板块新生代碰撞的结果,并被认作是典型的陆-陆碰撞[1.2.3.]地带。在此,我们报道了用深地震反射剖面方法进行本区地壳成像的第一个结果,试验的100km长剖面,布置在特提斯喜马拉雅(TethyanHimalaya)最南端,且跨过了喜马拉雅山脊,接近高喜马拉雅(HighHimalaya)地带,剖面显示了在地壳中部有一强反射带。它可能代表了一个活动的道冲断裂,印度板块是沿此断裂俯冲到藏南之下;上地壳反射使人们联想到上地壳存在着大规模的叠瓦状结构;莫霍反射来自本区双倍正常地壳厚度的巨厚地壳的底部。这些结果对西藏南端地壳增厚,是由于印度大陆地壳整体俯冲到包括特提斯喜马拉雅地区地壳之下的观点,给予了实质性的支持。 相似文献
27.
根据中、美两国合作开展的西藏深反射地震结果,提出雅鲁藏布江缝合带(YZS)的"双陆内俯冲"构造模式和缝合带南、北分别存在着不同特征的、规模不一的部分熔融层;提出YZS处断裂向深部延深有限,认为YZS处地壳增厚有4种机制:①地壳规模的大的俯冲增厚;②上部地壳内的俯冲和背冲增厚;③下地壳内的底部垫托增厚和挤压增厚;④深部熔融体的向上挤入而引起的地壳增厚.提出可能存在两条大的伸展性断裂,造成江孜南、北地块间出现了大升降. 相似文献
28.
中国南方海相油气勘探研究新进展 总被引:9,自引:2,他引:9
Petroleum Exploration Project Management of South China CNPC Hangzhou Institute of Petroleum Geology CNPC - Xixi Rd. Hangzhou P.R.China 《海相油气地质》1997,2(2):1-15
中国南方海相油气勘探研究取得6个方面的进展;1.重塑了华南板块的四个构造演化阶段,将华南板块划分出三个构造区,一个火山岩区和两个造山带,并了南方构造格架与演化对油气地质条件的控制.2.分析了华南板块南北两个大陆边缘沉积盆地的二级超旋回层序,凝缩层段及其与烃源岩发育的关系,并重点分析了区域性四套主力烃源岩的特点;3.提出了华南板块北南两个前陆盆地带的发育对中国南方海相油气的后期保存起着重要的作用。 相似文献
29.
楚雄盆地含油气系统分析及勘探目标选择 总被引:6,自引:2,他引:4
楚雄盆地是在扬子板块西南大陆边缘上发育起来的晚三叠世-早白垩世前陆盆地与晚白垩世-第三纪陆内湖盆叠置的构造-沉积残留盆地。 相似文献
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