我国海啸灾害及预警现状与建议

本文给出了海啸定义及其它有关概念与术语,简要给出了我国及全球的海啸灾害.全面介绍了我国海啸监测能力、预警现状、研究成果以及有关国际合作的情况,重点介绍了我国自主研制的海啸数值模式,利用该模式我们模拟了2004年12月26日发生在印度洋大海啸以及假想的发生在我国南海的海啸对周边国家的影响.对海啸预警中存在的问题及未来急需开展的工作,作者也将一一给予阐述.     

海啸灾害与预警

地震海啸是最严重的自然灾害之一。本文对海啸的定义、性质、特征、历史上和近代的中国和世界的严重地震海啸灾害作了介绍。同时简单地介绍了海啸预警系统的主要内容。     

美国夏威夷州海啸灾害研究概述

夏威夷是世界上最易遭受海啸洪水灾害的地区之一。本文介绍了美国夏威夷群岛在海啸实时监测和数值模拟方面的研究进展,并重点介绍了夏威夷海啸预警系统的组成与作用。     

海啸预警与第四纪古海啸沉积记录研究进展

海啸对人类的生命和财产安全构成巨大的威胁,2004年12月26日苏门答腊特大海啸的发生,引起了国际社会对海啸预警问题的重视,并进一步认识到古海啸沉积研究的重要性.介绍了国际上对海啸预警和古海啸沉积研究的进展,重点综述古海啸沉积的研究现状、研究方法与识别标志.最近20年来,研究者们着重对滨岸、浅海或陆地上的现代海啸沉积和古海啸堆积物进行研究,而对深水区域的古海啸记录研究很少.笔者认为在海啸多发海域的深水区进行长柱状沉积物取样,通过沉积学和地球化学分析研究,把古海啸沉积从海底正常沉积中识别出来,再结合定年,有助于恢复古海啸史,明确长期的灾害风险.     

并非虚设的海啸预警演习

2004印度洋大海啸以至少25万条生命的代价，引发了人们对建立全球海啸预警机制的思考。[编者按]     

基于GIS的海啸预警信息系统集成框架

预先利用CTSU海啸数值模型模拟出可能存在的各种假想海啸源.运用海啸数值计算模型,分别就5个不同震级(6.5、7.0、7.5、8.0、8.5)、6个不同震源深度(0、20、40、60、80、100 km)的1 400多个假想海啸源进行海啸数值模拟,模拟的时间步长为1 min,空间网格以2′为间隔,模拟区域为104°～132°N、0°～32°E.按照引发海啸的级别不同,将数模计算结果存贮于数据库之中,并在应用时基于GIS网格建立快速内插索引,自动输出预警信息,并在GIS界面中提供可视化表达.系统采用模板文件来定义预警分析的范围和内容.在海啸预警分析时,系统主要使用以下4个模板:(1) 海啸源网格模板,该模板定义了整个预警场中可能存在的海啸源地理位置和相关属性;(2) 海啸预警网格框架模板,此模板定义了整个海啸预警分析场中最后需要汇总的岸线网格位置;(3) 海啸预警岸段网格模板,该模板用来定义预警网格归于哪一个岸段;(4) 海啸预警城市网格模板,这个模板可以定义用户最为关心的重点城市的海啸预警信息.系统采用GIS界面,预警分析操作十分简单,系统运算也非常快,输入地震的精确位置、地震强度以及震源深度3个参数后,系统将自动执行一系列运算,在1～2 min内便可计算出所有海啸预警信息,并自动将预警信息在GIS界面中显示出来.最终以web网页的形式向公众发布海啸预警信息,达到了快速海啸预警分析的目的.网页开发采用Ajax技术,同时借助Google Maps API函数实现了预警信息的显示与维护.网络客户端仅需要1个浏览器,就可以实现有关信息的查询.系统在海量数据存贮、快速查询和分析等方面较好地解决了相关的技术难点,它对提高海啸防灾减灾科学决策能力具有重要意义.     

海啸灾害数值预报技术研究现状

海啸数值预报技术在海啸预警、防灾减灾工作及海啸物理机制研究工作中都具有举足轻重的作用,特别是在海啸预警及海啸防灾减灾工作中扮演着重要的角色.根据海啸产生及海啸波传播的特征,分别总结了海啸源产生数值模型、海啸传播和淹没模型的研究现状,重点介绍了当前主流地震海啸数值预报模型数值预报技术的发展、预警系统建设及应用现状.旨在为...     

代号“06太平洋巨浪”海啸预警演习

此次演习的成功向我们证明,我国在接收地震海啸信息、确认海啸风险并制作发布针对我国沿海地区的海啸警报、通信系统有效性及政府响应速度方面已经初步具备了对突发越洋海啸灾害的预警能力。     

基于海底压力测量的海啸预警方法研究

海啸是一种具有极大破坏力的海洋灾害,及时准确的海啸预报可大幅降低人民生财产损失。文中介绍了一种新的海啸灾害预警方法。该方法针对海啸预警需求,分析海啸波和海洋中的其他波动特性,以海底高精度压力测量为核心并消除噪声信号影响,可实现深海远距离海啸实时预警。以该方法为基础研制的海啸监测仪可实时监测并识别海啸波,从根本上降低海啸预警误报、漏报的概率,提高海啸预警系统的性能,及时为决策者提供信息,有效降低海啸灾害带来的损失。     

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)。     

海啸波数值模拟的研究现状

介绍海啸特点及主要分布状况,对比现在常用的海啸模拟数学模型,并分析数值模拟海啸的研究中存在的问题及研究进展,最后提出对未来进行精确的海啸数值模拟研究的一些展望。     

局地海啸波传播数学模型的研究

推导了地震海啸波传播的理论方程,并时局地地震海啸情况下的理论方程进行了求解.基于Boussinesq方程出发,建立了二维局地海啸渡传播数学模型;对局地海啸进行了数值计算,计算方法采用有限差分方法.差分格式采用交替方向隐格式,即ADI方法.利用该模型对发生在台湾海峡的一次地震海啸进行了模拟计算.将计算结果与理论方程的计算结果以及实际情况进行了对比.计算结果较好.为局地海啸波传播提供了一种模拟方法.     

Propagation Mechanisms of Incident Tsunami Wave in Jiangsu Coastal Area, Caused by Eastern Japan Earthquake on March 11, 2011

At 13:46 on March 11, 2011 (Beijing time), an earthquake of Mw=9.0 occurred in Japan. By comparing the tsunami data from Guanhekou marine station with other tsunami wave observation gathered from southeast coastal area of China, it was evident that, only in Guanhekou, the position of the maximum wave height appeared in the middle part rather than in the front of the tsunami wave train. A numerical model of tsunami propagation based on 2-D nonlinear shallow water equations was built to study the impact range and main causes of the special tsunami waveform discovered in Jiangsu coastal area. The results showed that nearly three-quarters of the Jiangsu coastal area, mainly comprised the part north of the radial sand ridges, reached its maximum tsunami wave height in the middle part of the wave train. The main cause of the special waveform was the special underwater topography condition of the Yellow Sea and the East China Sea area, which influenced the tsunami propagation and waveform significantly. Although land boundary reflection brought an effect on the position of the maximum wave height to a certain extent, as the limits of the incident waveform and distances between the observation points and shore, it was not the dominant influence factor of the special waveform. Coriolis force’s impact on the tsunami waves was so weak that it was not the main cause for the special phenomenon in Jiangsu coastal area. The study reminds us that the most destructive wave might not appear in the first one in tsunami wave train.     

Application of Boundary Collocation Method to Two-dimensional Wave Propagation

Boundary Collocation Method (BCM) based on Eigenfunction Expansion Method (EEM), a new numerical method for solving two-dimensional wave problems, is developed. To verify the method, wave problems on a series of beaches with different geometries are solved, and the errors of the method are analyzed. The calculation firmly confirms that the results will be more precise if we choose more rational points on the beach. The application of BCM, available for the problems with irregular domains and arbitrary boundary conditions, can effectively avoid complex calculation and programming. It can be widely used in ocean engineering.     

卫星测高技术在监测海啸现象中的研究及应用

利用卫星测高技术,通过共线平差和沿轨、垂直轨迹测高大地水准面梯度的计算,得到了海啸发生2个小时后的海面波高和海面梯度异常现象,为利用卫星测高技术监测海啸、模拟海啸现象提供了依据。     

Energetics of the Tsunami of 26 December 2004 in the Indian Ocean: A Brief Review

The energetics of the most destructive tsunami in historical time, and that of the under ocean earthquake that triggered this tsunami of 26 December 2004 in the Indian Ocean have been briefly reviewed. This latest tsunami has several other unique characteristics besides being one of the worst natural disasters in human history. It is the first truly global tsunami after modern seismographic and sea level monitoring networks have been put in place. It was the first tsunami on record detected by a satellite, even though at present, global satellite coverage of the oceans for real time tsunami detection is not adequate. Finally, the energy associated with the tsunami and the earthquake that triggered it is so large that speculation has been made about the normal modes of oscillation of the earth, that were triggered by the earthquake as well as some suggestions, that some of the earth's rotational characteristics may have temporarily changed to a discernible degree. Here, we briefly review the energetics of the tsunami and the earthquake that triggered it.     

A mathematical model of calculating local tsunami wave source constraints and propagation

This paper presents a local tsunami simulation, including the initial displacement field model of tsunami source and tsunami wave propagation model. We deduced the tsunami wave equation; applied the ma...     

Wave Attenuation and Friction Coefficient on the Coral-Reef Flat

Several sets of S4 direction-wave-current-tide meters have been deployed on the coral-reef fiat of Yongshu Reef in the sea area of Nansha Islands. Based on the observational sea wave data, the attenuation characteristics of the waves propagating on the coral reef flat, the bottom friction coefficients and the transfer of wave energy are discussed in the paper. The results show that, in the relative depths of 0. 0613- 0.0867, the wave height attenuation per unit distance of wave propagation is 22.09 %-46.56%, with an average of 31.35 % ; the wave energy, attenuation coefficient, 33.74 %- 53.22%, with an average of 43.61%. The average of the bettom friction coefficients on the coral-reef flat is 0. 1346,which is about 10 times thai on the sand or silt bottom. In the couse of propagation on the reef flat, the waves sustain more loss in high frequency than in low frequency and the spectral energy transfers to the low frequency. These results may be used for reference in island and reef engineering.     

Applications of A Numerical Model to Wave Propagation on Mild Slopes

Based on the mild slope equation that has heen deeomposed inlo three equations related to wave phase function, wave amplitude and wave approach angle, a refraction-diffraction model is developed. The finite difference method has been selected as the solution method. The model results are compared with experimental results and the model is applied to coastal waters of the Fethiye Bay, whieh is located at the Mediterranean Sea of Turkey.