Evaluation of the Parameters of Tsunami Waves along the South Coast of the Crimean Peninsula

Within the framework of a nonlinear model of long waves, we present the estimates of the parameters of tsunami waves along the south coast of the Crimean Peninsula (from Cape Khersones to Cape Meganom) with a space resolution of 2.5 km. The numerical analysis is carried out for four typical positions of the elliptic zones of generation and the range of magnitudes 6.5–7.5. We study the space structure of waves and determine the amplitudes and periods of oscillations of the level at 11 points of the analyzed part of the coastline of the Black Sea. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 3 – 10, May–June, 2005.     

Numerical Investigation of Vertical Turbulent Jets in Different Types of Waves

The effects of various types of waves on vertical plane turbulent jets are studied numerically in the paper. A three-dimensional numerical model in σ-coordinate is developed to study these problems by use of large eddy simulation method. Turbulence is modeled by a dynamic coherent eddy model. Numerical results including the distribution of velocity,the decay law of the mean velocity along axis,the turbulent Reynolds stresses and the volume flux per unit width without wave,in the first-order Stokes waves,in ...     

岩石孔隙及泥质含量对地震波速度的影响

孔隙和泥质是影响地震波速度的重要因素。阐述了孔隙和泥质含量对地震波速的影响机理、影响程度以及求取孔隙度和泥质含量的方法。     

Numerical Investigating of Vertical Turbulent Jets in Different Types of Waves

The effects of various types of waves on vertical plane turbulent jets are studied numerically in the paper. A three-dimensional numerical model in σ -coordinate is developed to study these problems by use of large eddy simulation method. Turbulence is modeled by a dynamic coherent eddy model. Numerical results including the distribution of velocity, the decay law of the mean velocity along axis, the turbulent Reynolds stresses and the volume flux per unit width without wave, in the first-order Stokes waves, in the second-order Stokes waves, in the fifth-order Stokes waves, in the solitary waves and in random waves are compared and analyzed. A focus on coherent structures, probability density functions and correlation functions of jets is also investigated. The numerical results are of great theoretical importance for understanding jet turbulent behaviors in different types of waves.     

Acquisition and Inversion of Dispersive Seismic Waves in Shallow Marine Environments

Two types of dispersive seismic waves have been acquired in different geological settings to investigate the potential to reveal the elastic parameters of the shallow marine subsurface. Scholte waves as well as acoustic guided waves are excited by a near-surface towed airgun, and recorded using two acquisition methods: (1) the towed-acquisition system using a hydrophone streamer towed close to the sea floor, and (2) the stationary-receiver method using Ocean-Bottom Seismometers and/or Hydrophones (OBS/OBH). Our diverse data sets reveal that the spatial sampling of the wavefield required to avoid aliasing may vary significantly for different geological settings. Scholte waves are characterised by a few distinct modes observed at low frequencies and low phase velocities. Their dispersion is mainly controlled by the depth profile of the shear-wave velocity. Acoustic guided waves show profound amplitude variations of numerous higher modes over a broad frequency range. These are sensitive to shear-wave velocity, but more sensitive to compressional-wave velocity than Scholte waves are. To avoid the identification of distinct modes we infer 1-D models of elastic parameters of the subsurface from the inversion of the full wavefield spectra of acoustic guided waves. In the Siberian Laptev Sea we infer the presence of a soft sediment layer (8–10 m) with a well resolved strong S-velocity gradient (150–450 m/s). In the Baltic Sea a low P-velocity layer with a strong vertical gradient (1250–1440 m/s) corresponding to a post-glacial gassy mud layer could be resolved, which agrees well with the sediment stratigraphy derived from a gravity core.     

热带印度洋Rossby波的基本特征

<正>海洋斜压长Rossby波在海洋动力学中占据重要地位,是物理海洋学研究的一个重要任务。它维持并影响大洋西边界流,是海盆内能量传播的主要机制,是海洋对大气驱动的主要响应现象(Pedlosky,1979;Gill,1982)。20世纪70年代以来,XBT资料的积累使人们能够从水文资料中,特别是次表层海温的变化中发现大尺度Rossby波的存在依据(White,1977;Kessler,1990),且集中在     

Characteristics of Parameters for Local Scour Depth around Submarine Pipelines in Waves

The purpose of this study is to investigate the characteristics of parameters for local scour depth around submarine pipes due to waves. Because it is impossible to consider all the factors that influence the scour, it is reasonable to investigate the correlations between parameters and scour. The experimental works about scour were performed for the conditions of 40, 60, 90 m pipe diameter, various wave periods, and wave height in the case of horizontal bed and 1/10 slope bed, respectively. Analyzing the results of experiments, the Reynolds number, Shields parameter, Keulegan-Carpenter number, Ursell number, and Modified Ursell number were estimated. The correlations between the relative scour depth, which is the maximum equilibrium local scour depth divided by the pipe diameter, and 5 parameters were analyzed. It was shown that there was hardly any correlation with the Reynolds number. In the case of a horizontal bed, the Keulegan-Carpent number had the highest correlation, but in the case of the slope bed the correlation was greatly reduced. The modified Ursell number showed a high correlation regardless of the type of bed.     

热带印度洋Rossby波的基本特征

Long wavelength baroclinic oceanic Rossby waves are of interest because they are the main mechanism of energy transfer among the oceanic basins as the rotating fluid adjusts under the forcing of gravity and buoyancy,They play an important role in dynamics and thermodynamics in the ocean.The signature of them is evident from the altimeter measurements.Sea surface beight derived from the multiple ocean satellite altimeter missions over 1993～2008 is analyzed to systematically investigate the characteristics of the Rossby waves in the tropical Indian Ocean,by jointly adopting 2D-FFT,2D-Radon Transform,Complex Empirical Orthogonal Function and the classic linear theory methods.Results are as follows.The energy of Rossby wave is mainly concentrated between 5°S～18°S.Annual Rossby wave can be observed all over the whole badin,whereas semi-annual Rossby wave can bw only detected in the equatorial area, and inter-annual Rossby wave in the off-equatorial region.The phase speeds of Rossby waves detected from altimeter satellites are basically in agreement with the calculation based on the classic linear theory, but the former are some slower(faster) north(south)of 15°S than the later,Furthemore,it is indicated from the CEOF analysis that the annual Rossby waves is apparent in the Bay of Bengal,Arabian Sea ,and the open south Indian Ocean,whereas inter-annual Rossby wave mainly presents in the south Indian Ocean ,and eastward Kelvin wave is dominant along equator.     

Response Characteristics of Load on Vessels in Waves

Considering the requirement of direct design and fatigue test for ships and floating structures byuse of FEM technique,a computational procedure of spectral analysis for wave load on the hull surface is de-veloped in this paper.The response of hydrodynamic pressure on the body surface to a designated sea state forships and floating structures is calculated by use of the revised strip method with the hull bound perturbationflow concept.The spectral function of wave load for the defined point on the body surface can be determinedfrom the Wiener-Khinhin theorem and the characteristic load value can be also obtained from spectral mo-ment analysis.A container ship is taken as a computational example and the sample of wave load with a cer-tain probability and corresponding encountered frequency is provided.     

Nonlinear Lagrangian Breaker Characteristics for Waves Propagating Normally Toward A Mild Slope

Because of shoaling, refraction, friction, and other effects, a surface-wave propagating on a gently sloping bottom of slope will eventually break. In this paper, by nonlinearizing the problem and using a perturbation method, an analytical solution for the velocity potential is derived to the second order for the bottom slope a and the wave steepness e in a Eulerian system. Then, the wave profile and the breaking wave characteristics are found by transforming the flow field into a Lagrangian system. By use of the kinematic stability parameter （K. S. P. ）, new theoretical breaker characteristics are derived. Thus, the linear theories of other scholars are extended to breaking waves. A Comparison of the present analytical solution with experimental studies of other scholars shows reasonable agreement except that the breaking depth is underestimated.     

大洋Rossby波动纬向传播速度的分布特征

利用1992年10月22日-2001年7月17日扣除年循环的T／P和ERS-1／-2的卫星融合高度计资料，应用二维Radon变换方法，对太平洋和大西洋的洋盆东部、西部的大洋Rossby波的纬向传播速度进行了分析与对比，并将二者分别与经典线性理论值比较，得出洋盆西部的Rossby波普遍比洋盆东部传播要快；中纬度海域大洋Rossby波的传播速度观测值与理论值的比率小于前人结果；并且在热带及副热带海域，大洋Rossby波的传播速度的观测值要低于理论值的结论。     

河道砂岩体地震反射特征分析

按河道形态,河流分为４类：（１）顺直河;（２）曲流河;（３）辫状河;（４）网状河。根据河道砂岩体主体的宽（ｗ）与（ｈ）高之比,河道砂岩体分为带状砂岩体（ｗ∶ｈ小于１５）和席状砂岩体（ｗ∶ｈ大于１５）。在参考前人资料的基础上,总结了在横切河道的地震剖面上河道砂岩体的反射形态、结构及振幅变化。重点介绍了曲流河内侧沙洲地震勘探,以及三维地震勘探技术在寻找河道砂岩体方面的应用。并强调指出,在河道砂岩体地震勘探中,应当加强地震资料与钻井资料、测井资料的结合。     

Seismic and Meteorological Tsunami Contributions in the Manzanillo and Cabo San Lucas Seiches of September 14, 1995

Seismic generated sea waves from the September 14, 1995, Mexico earthquake are favored over the waves generated by hurricane Ismael to be the cause of the increase in seiche amplitudes in Manzanillo and Cabo San Lucas tide stations. The arguments are based on travel time computations from the seismic source and the moving meteorological source. A relatively sudden increase in seiche amplitudes is consistent with the arrival time of the seismic tsunami, and previously existent background is likely produced by incoming waves from the hurricane.     

Seismic and Meteorological Tsunami Contributions in the Manzanillo and Cabo San Lucas Seiches of September 14, 1995

Seismic generated sea waves from the September 14, 1995, Mexico earthquake are favored over the waves generated by hurricane Ismael to be the cause of the increase in seiche amplitudes in Manzanillo and Cabo San Lucas tide stations. The arguments are based on travel time computations from the seismic source and the moving meteorological source. A relatively sudden increase in seiche amplitudes is consistent with the arrival time of the seismic tsunami, and previously existent background is likely produced by incoming waves from the hurricane.     

Tsunami flooding extension for coastal zones of Mexico

Abstract

Joint probabilities of runup height due to astronomical tides and tsunamis are calculated for five bays on the Pacific Ocean coast of Mexico. Runup heights equaled or exceeded on the average of once per 100 years, and once per 200 years, for those bays, are evaluated. Calculations are based on wave height probabilities obtained from sets of harmonic constituents and tsunami heights recorded during the last 28 years at tidal stations on each location.

Extension of potential tsunami terrestrial flooding for populated coastal zones around those bays can be determined from the previous results. One case is illustrated showing endangered features in the hazardous zones, and recommendations to prevent casualties and property damages are given.     

印度洋海啸灾害特点及其对工程防御的启示

印度洋海啸现场调查表明,海啸灾害不同于地震和洪水灾害。海啸通过高水位淹没、浪涌冲击对海边地势低平地区的房屋、道路、桥梁、机场、给排水、供电、通讯等设施以及车辆、船只造成严重破坏。海啸上岸后,由于巨大的冲力,将夹带一些破损建筑产生的固体漂浮物一同前进,破坏力更强。由于淹没、浪涌、冲毁建筑物压埋以及漂浮物冲击等综合作用,造成人员死亡率极高,所过之处,财产皆空。抗御海啸灾害的工程措施主要包括:合理规划(避让、削弱、分流、阻挡)和科学设计(潜在海啸灾害等级划分、结构性态决策、海啸荷载确定、抗海啸分析、构造设计)。     

Tsunami warning system for the pacific coast of Canada

Abstract

The Tsunami Warning System for the Pacific Coast of Canada, which is part of the International Tsunami Warning System for the Pacific Ocean, is reviewed and major problems are identified. The efficiency of the present warning system is examined in view of the prediction by the international seismological community that major earthquakes are likely to occur in various seismic gaps around the Pacific rim in the near future. Whereas the present system is more or less adequate for the outer coast, at present there is no warning system for tsunamis generated locally in the Straits of Juan de Fuca and Georgia, or in Puget Sounds.     

Research on Characteristics of Density Current Under the Action of Waves

In this paper,the characteristics of density current under the action of waves are describedwith the help of flume experiment and theoretical analysis.The study shows that turbid water under the ac-tion of the waves can present three types of motion,i.e.significant stratification,fragile stratification andstrong mixing.The motion of turbid water presents significant stratification when(H/D)/△ρ/ρ~(1/2)≤4.5,generally this state is known as density current.The formulas of motionvelocity,thickness,and discharge of density current moving on horizontal bottom are derived by use of ba-sic equations such as momemtum equation,equation of energy conservation and continuity equation offluid.The time-average velocity and the thickness of density current under the action of waves have a rela-tionship with such parameters as relative density(△ρ/ρ),wave height(H),and water depth(D).Whenthese parameters are determined,the time-average thickness and motion velocity of density current are al-so determined.The relat     

大西洋欧洲沿海的海浪特点

利用１９８０年－１９９０年中央气象船舶报资料,以２°×２°网络,对大西洋欧洲附近沿海包括地中海西口、欧洲近海、英吉利海峡西口的重要海域,进行了累年逐月的统计计算和分析研究,每个网格中,一个月所含有的样本数一般为１２２－１６２２次,其中最多的测次达１９４７次,最少的测次为４９次。文章介绍了该区的风、浪、涌分布特点和变化规律。     

Tsunami Inundation Modelling for the Coast of Kerala,India

The disastrous tsunami of December 26, 2004, exposed the urgent need for implementing a tsunami warning system. One of the essential requirements of a tsunami warning system is the set up of tsunami inundation models which can predict inundation and run-up along a coastline for a given set of seismic parameters. The Tsunami Warning Centre and the State/District level Disaster Management Centres should have tsunami inundations maps for different scenarios of tsunami generation. In the event of a tsunamigenic earthquake, appropriate decisions on issue of warnings and/or evacuation of coastal population are made by referring to such maps. The nature of tsunami inundation and run-up along the Kerala coast for the 2004 Sumatra and 1945 Makran, and a hypothetical worst-case scenario are simulated using the TUNAMI N2 model and the results are presented in this paper. Further, scenarios of tsunami inundation arising out of possible rise in sea level as projected by the Intergovernmental Panel on Climate Change (IPCC 2001) are also simulated and analysed in the paper. For the study, three representative sectors of the Kerala coast including the Neendakara-Kayamkulam coast, which was the worst hit by the 2004 tsunami, are chosen. The results show that the southern locations and certain locations of central Kerala coast are more vulnerable for Sumatra when compared to Makran 1945 tsunami. From the results of numerical modelling for future scenarios it can be concluded that sea level rise can definitely make pronounced increase in inundation in some of the stretches where the backshore elevation is comparatively low.