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61.
文中阐述了中国数字地震台网数据管理中心(CDSN DMC)日常工作软件的升级和升级后新软件的主要功能,并结合新软件的主要命令及运行实例,对升级后软件的实际应用作了简要叙述。 相似文献
62.
The origin of the Ryukyu Current(RC) and the formation of its subsurface velocity core were investigated using a 23-year(1993–2015) global Hybrid Coordinate Ocean Model(HYCOM) dataset. The volume transport of the RC comes from the Kuroshio eastward branch(KEB) east of Taiwan and part of the North Pacific Subtropical Gyre(pNPSG). From the surface to 2 000 m depth, the KEB(p-NPSG) transport contributes 41.5%(58.5%) to the mean total RC transport. The KEB originally forms the subsurface velocity core of the RC east of Taiwan due to blockage of the subsurface Kuroshio by the Ilan Ridge(sill depth: 700 m). Above 700 m, the Kuroshio can enter the East China Sea(ECS) over the Ilan Ridge, meanwhile, the blocked Kuroshio below 700 m turns to the right and flows along the Ryukyu Islands. With the RC flowing northeastward, the p-NPSG contribution strengthens the subsurface maximum structure of the RC owing to the blockage of the Ryukyu Ridge. In the surface layer, the pNPSG cannot form a stable northeastward current due to frequent disturbance by mesoscale eddies and water exchange through the gaps(with net volume transport into ECS) between the Ryukyu Islands. 相似文献
63.
基于多层DEM与QTPV的混合数据模型及其在地质建模中的应用 总被引:7,自引:1,他引:7
提出一种基于多层DEM与似三棱柱体元(QTPV)的混合三维数据模型。模型包含顶点、线段(棱边、三角形边)、三角形、侧面四边形、似三棱柱体元和DEM 6个基本元素,同时包含点对象、线对象、面对象、体对象、复杂对象、空间对象等6个对象。设计了6个基本元素和2种地质对象的数据结构和它们之间的拓扑关系。研究了基于原始采样点和基于内插点的两种建模方法。以模拟数据和地质钻探数据对开发的原型系统进行验证。研究表明,基于多层DEM与似三棱柱体元的混合三维数据模型具有同时表达空间对象的表面和内部结构的能力,适合地质勘探领域的三维建模。 相似文献
64.
韧性剪切变形对岩石地球化学行为的制约——以北阿尔金巴什考供韧性剪切带为例 总被引:6,自引:0,他引:6
韧性剪切变形对岩石地球化学行为的制约一直是地质学家们探讨的课题。本文以构成北阿尔金红柳沟——拉配泉俯冲碰撞杂岩带与北阿尔金地块边界的巴什考供斜向逆冲型韧性剪切带为例,通过对韧性剪切带内花岗岩变形前后不同变形强度构造岩的地球化学组成进行对比,确定等比线斜率,探讨韧性变形对岩石体积和成分变异的影响。计算结果表明,在糜棱岩化过程中,糜棱岩化花岗岩体积亏损21%,花岗质糜棱岩体积亏损31%。质量平衡计算结果和等比线图表明,韧;陛剪切作用导致SiO2,流失量最大,A12O3、K2O及Ba、Rb、Sr等都有不同程度的丢失,显示出较强的活动性,MnO、P2O5、Sc位于等比线上或附近,表现出相对的稳定性。岩石中活动组分的变异是流体渗滤作用引起的,不活动组分的变异是体.积亏损造成的。 相似文献
65.
Tanju Akar 《水文科学杂志》2020,65(6):984-994
ABSTRACTSediment accumulation in a river reservoir is studied by stochastic time series models and analytical approach. The first-order moving average process is found the best for the suspended sediment discharge time series of the Juniata River at Newport, Pennsylvania, USA. Synthetic suspended sediment discharges are first generated with the chosen model after which analytical expressions are derived for the expected value and variance of sediment accumulation in the reservoir. The expected value and variance of the volume of sediment accumulation in the reservoir are calculated from a thousand synthetic time series each 38 years long and compared to the analytical approach. Stochastic and analytical approaches perfectly trace the observation in terms of the expected value and variability. Therefore, it is concluded that the expected value and variance of sediment accumulation in a reservoir could be estimated by analytical expressions without the cost of synthetic data generation mechanisms. 相似文献
66.
CHEN Meixiang) ZUO Juncheng) LI Peiliang) DU Ling) and LI Lei)) Oceanography Department Ocean University of China Qingdao P. R. China ) Key Laboratory of Coastal Disaster Defence Ministry of Education Hohai University Nanjing P. R. China 《中国海洋大学学报(英文版)》2007,6(2):117-124
Based on a ship survey during January 1998, the characteristics of the flow, the thermohaline properties and the volume transport of the Arabian Sea are discussed. A strong westward flow exists between 10.5?N and 11?N, part of which turns to the south as the Somali current near the coast at about 10?N and the rest turns north. At the passage between the African continent and the So- cotra Island, the northern branch separates into two flows: the left one enters the passage and the right one flows eastward along the southern slope of the island. Off the island the flow separates once more, most of it meandering northeast and a small fraction flow- ing southeast. Volume transport calculation suggests that the tidal transport is one or two orders of magnitude smaller than the total transport in this region and it becomes more important near the coast. The average velocity of the flow in the upper layer (0-150 m) is about 20 cm s-1, with a maximum of 53 cm s-1 appearing east of the Socotra Island, and the subsurface layer (200-800 m) has an aver- age velocity of 8.6 cm s-1; the velocity becomes smaller at greater depths. The depth of the seasonal thermocline is about 100 m, above which there is a layer with well mixed temperature and dissolved oxygen. High-salinity and oxygen-rich water appears near the surface of the northern Arabian Sea; a salinity maximum and oxygen minimum at 100 m depth along 8?N testifies the subduction of surface water from the northern Arabian Sea. Waters from the Red Sea and the Persian Gulf also influence the salinity of the area. 相似文献
67.
Larissa L. Maughan Eric H. Christiansen Myron G. Best C. Sherman Gromm Alan L. Deino David G. Tingey 《Journal of Volcanology and Geothermal Research》2002,113(1-2)
Unusual monotonous intermediate ignimbrites consist of phenocryst-rich dacite that occurs as very large volume (>1000 km3) deposits that lack systematic compositional zonation, comagmatic rhyolite precursors, and underlying plinian beds. They are distinct from countless, usually smaller volume, zoned rhyolite–dacite–andesite deposits that are conventionally believed to have erupted from magma chambers in which thermal and compositional gradients were established because of sidewall crystallization and associated convective fractionation. Despite their great volume, or because of it, monotonous intermediates have received little attention. Documentation of the stratigraphy, composition, and geologic setting of the Lund Tuff – one of four monotonous intermediate tuffs in the middle-Tertiary Great Basin ignimbrite province – provides insight into its unusual origin and, by implication, the origin of other similar monotonous intermediates.The Lund Tuff is a single cooling unit with normal magnetic polarity whose volume likely exceeded 3000 km3. It was emplaced 29.02±0.04 Ma in and around the coeval White Rock caldera which has an unextended north–south diameter of about 50 km. The tuff is monotonous in that its phenocryst assemblage is virtually uniform throughout the deposit: plagioclase>quartz≈hornblende>biotite>Fe–Ti oxides≈sanidine>titanite, zircon, and apatite. However, ratios of phenocrysts vary by as much as an order of magnitude in a manner consistent with progressive crystallization in the pre-eruption chamber. A significant range in whole-rock chemical composition (e.g., 63–71 wt% SiO2) is poorly correlated with phenocryst abundance.These compositional attributes cannot have been caused wholly by winnowing of glass from phenocrysts during eruption, as has been suggested for the monotonous intermediate Fish Canyon Tuff. Pumice fragments are also crystal-rich, and chemically and mineralogically indistinguishable from bulk tuff. We postulate that convective mixing in a sill-like magma chamber precluded development of a zoned chamber with a rhyolitic top or of a zoned pyroclastic deposit. Chemical variations in the Lund Tuff are consistent with equilibrium crystallization of a parental dacitic magma followed by eruptive mixing of compositionally diverse crystals and high-silica rhyolite vitroclasts during evacuation and emplacement. This model contrasts with the more systematic withdrawal from a bottle-shaped chamber in which sidewall crystallization creates a marked vertical compositional gradient and a substantial volume of capping-evolved rhyolite magma. Eruption at exceptionally high discharge rates precluded development of an underlying plinian deposit.The generation of the monotonous intermediate Lund magma and others like it in the middle Tertiary of the western USA reflects an unusually high flux of mantle-derived mafic magma into unusually thick and warm crust above a subducting slab of oceanic lithosphere. 相似文献
68.
介绍了基于SEED波形文件运行率计算的技术和实现方法,介绍了SEED文件中标识时间的特殊掩码、时间片的具体格式和程序的实现,并给出了与其相关的部分源代码. 相似文献
69.
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