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961.
962.
怀4井汞量异常与地震的关系 总被引:6,自引:3,他引:3
首先介绍了怀来4井地质构造情况,然后根据怀来4井1989-1998年水汞观测资料,分析了4次中强地震前汞量异常与地震的关系。结果显示,怀来4井汞量异常与地震前的地震活动异常有较好的对应关系。 相似文献
963.
1950—2000年中国地磁测量地磁图与地磁研究 总被引:7,自引:2,他引:5
为纪念“3912”建队三十周年,本文回顾了1950-2000年中国地磁测量和地磁图,回顾了“3912”任务的光辉业绩,阐述了“3912”任务的学术意义和应用价值。 相似文献
964.
中国及邻区岩石层密度三维结构 总被引:4,自引:0,他引:4
利用中国及邻区2×2S波速地震三维层析成像和30’×30’重力资料.首先采用密度差与S波速差的经验关系式,建立起中国及邻区的岩石层密度初始模型,再利用布格重力异常进行阻尼最小二乘法反演,得到该区岩石层三维密度分布结果.反演结果表明:1.中国地区密度异常分布与大地构造分区有着明显的相关性,高密度区对应古老地块,低密度区对应高原及山区,在不同块体边界存在着密度异常梯级带;2.岩石层地幔密度分布与地壳密度分布特征不一致. 相似文献
965.
Behaviour of particle-laden flows into the ocean: experimental simulation and geological implications 总被引:3,自引:0,他引:3
The behaviour of subaerial particle-laden gravity currents (e.g. pyroclastic flows, lahars, debris flows, sediment-bearing floods and jökulhlaups) flowing into the sea has been simulated with analogue experiments. Flows of either saline solution, simple suspensions of silicon carbide (SiC) in water or complex suspensions of SiC and plastic particles in methanol were released down a slope into a tank of water. The excess momentum between subaerial and subaqueous flow is dissipated by a surface wave. At relatively low density contrasts between the tank water and the saline or simple suspensions, the flow mixture enters the water and forms a turbulent cloud involving extensive entrainment of water. The cloud then collapses gravitationally to form an underwater gravity current, which progresses along the tank floor. At higher density contrasts, the subaerial flow develops directly into a subaqueous flow. The flow slows and thickens in response to the reduced density contrast, which is driving motion, and then continues in the typical gravity current manner. Complex suspensions become dense flows along the tank floor or buoyant flows along the water surface, if the mixtures are sufficiently denser or lighter than water respectively. Flows of initially intermediate density are strongly influenced by the internal stratification of the subaerial flow. Material from the particulate-depleted upper sections of the subaerial flow becomes a buoyant gravity current along the water surface, whereas material from the particulate-enriched lower sections forms a dense flow along the tank floor. Sedimentation from the dense flow results in a reduction in bulk density until the mixture attains buoyancy, lifts off and becomes a secondary buoyant flow along the water surface. Jökulhlaups, lahars and debris flows are typically much denser than seawater and, thus, will usually form dense flows along the seabed. After sufficient sedimentation, the freshwater particulate mixture can lift off to form a buoyant flow at the sea surface, leading to a decoupling of the fine and coarse particles. Flood waters with low particulate concentrations (<2%) may form buoyant flows immediately upon entering the ocean. Subaerial pyroclastic flows develop a pronounced internal stratification during subaerial run-out and, thus, a flow-splitting behaviour is probable, which agrees with evidence for sea surface and underwater flows from historic eruptions of Krakatau and Mont Pelée. A pyroclastic flow with a bulk density closer to that of sea water may form a turbulent cloud, resulting in the deposition of much of the pyroclasts close to the shore. Dense subaqueous pyroclastic flows will eventually lift off and form secondary buoyant flows, either before or after the transformation to a water-supported nature. 相似文献
966.
重力活塞取样器取样技术研究 总被引:3,自引:0,他引:3
现代海洋沉积物柱状取样技术是一套综合性的高新技术系统,它一般应该包括:优良的取样器具,方便灵活的取样操作设备,高精度的定位导航仪器和高分辨率的地形、地貌、地层探测系统等四个方面。我国和先进国家相比,取样操作设备方面差距最大,应该成为我国今后取样技术研究和发展的重点 相似文献
967.
海洋沉积体系的定量模拟可分为仿真和勘察式模拟,后者的目标是建立沉积特征的连续谱、凝练新的科学问题。本文提出一个勘察式模拟的方法论框架,即根据控制方程确定自变量的定义域,进而由模拟计算给出应变量的值域,并结合物质收支平衡原理和“圆台状环礁”几何模型,以此方法预估环礁及其海底阶地物质输运和堆积格局。环礁是珊瑚礁的独特类型,其礁盘区提供了礁体生长和礁外坡、海底阶地堆积的几乎全部物源。结果表明,环礁自身生长受控于生物碎屑生产,而海底阶地的范围和沉积速率不仅决定于离礁悬沙通量,而且受到环礁外水深和海盆环流的制约。悬沙输运和重力流过程形成常态沉降和水下滑坡的交替沉积。此模型所预测的环礁沉积体系高程-面积曲线与南海环礁的实际曲线相对照,可获得环礁演化的机制信息。模拟结果还提示了需进一步研究的科学问题,如环礁生长规模及其控制机制、环礁沉积体系中周期性沉积的时间尺度、环礁外坡由于珊瑚生长自组织机制形成的重力流事件与地震等极端事件的对比和机制识别、环礁群的海底阶地沉积记录多样性、海面变化对环礁演化的影响和沉积记录、环礁人居环境安全等。 相似文献
968.
969.
KSS 31海洋重力仪配套接口子系统开发 总被引:1,自引:0,他引:1
介绍一种采用VC 语言开发成功的KSS 31型海洋重力仪导航系统适配的接口应用程序,对如何解决引进新型号设备与现有的系统(设备)集成(连接)问题有一定的借鉴作用。 相似文献
970.
The parameterization of gravity wave drag induced by sub-grid scale orography(GWDO), which has been used in the regional model based on the Global/Regional Assimilation and Prediction System for Tropical Mesoscale Model(GRAPES_TMM), is extended to include the effect of mountain flow blocking drag(MBD). The extended scheme is evaluated against non-GWDO parameterization, including a cold air outbreak over southern China and a monthly verification in February 2012. The experiment results show that the GWDO and MBD parameterization both improves the forecasting of the cold air outbreaks over southern China, as well as alleviations of system bias of GRAPES_TMM.(1) The extended scheme alleviates the strong southerly wind and high surface temperature simulation during the cold air outbreak, especially over northern Guangxi and Guangdong(NGG) province, where local high surface temperature simulation reduces nearly 5 degree.(2) The MBD parameterization improves southerly wind simulations over NGG, as well as surface temperature forecasts improvement over Guangxi, Guizhou province and southern Yunnan-Guizhou plateau(YUP), and low level southerly wind simulation improvement over intertidal zone over south China.(3) The formation of MBD is mainly in the mountain area(Wuyi, Daba mountain, east of YUP) and coastal area. The MBD over plateau, which is mainly formed at the west of 105°E, is stronger and thicker than that over Nanling mountain.(4) The improvement of GWDO and MBD parameterization is stable in model physics. MBD parameterization demonstrates more overall improvements in the forecasts than GWDO, and the larger of the model forecast error is, the greater improvements of MBD contribute to. Overall, the extended GWDO scheme successfully improves the simulations of meteorological elements forecasting during cold air outbreaks. 相似文献