Characteristics of Tsunami Damage to the Tide Walls in Iwate Prefecture from the Great East Japan Earthquake

This research paper describes the tsunami damage to tide walls observed using aerial photographs and field investigations at 13 locations along the coast of Iwate Prefecture, where significant tsunami damage occurred as a result of the Great East Japan Earthquake. This paper also summarizes the characteristics of the damage. The tide walls in Iwate Prefecture were constructed on a ria （hilly type） coast, this geographical feature of lwate being different from that of the other disaster areas, primarily Miyagi and Fukushima Prefectures. The results of our investigations show that all the devastated tide walls suffered from overflow before being damaged. In particular, the sloping and vertical type tide walls with slope protection were damaged by scouring of the infill sand or back fill soil due to the overflow of the tsunami. In the case of vertical type tide walls without slope protection, damage was caused by scouring of the back fill soil.     

The impact of the 2011 Tohoku earthquake tsunami disaster and implications to the reconstruction

The authors conducted a comprehensive study to identify the impact of the 2011 Tohoku tsunami disaster and to understand the lessons towards the reconstruction of Tohoku to build tsunami-resilient community. First, the authors identified the extent of tsunami inundation zone by field measurement and satellite remote sensing. A specific index for optical satellite images was applied for the extraction of tsunami inland penetration calibrated with the ground truth data (field survey data). Second, an integrated investigation of field measurement and aerial photo and video inspections with spatial information sciences was performed to understand the hydrodynamic aspect of tsunami inland penetration with a form of tsunami flow velocity and hydrodynamic force, and the preliminary results lead to new understandings of structural vulnerability against the 2011 tsunami with a form of tsunami fragility curve and an implication for land use management and relocation planning to reconstruct resilient coastal communities.     

Seismic Design of Offshore Wind Turbine Withstands Great East Japan Earthquake and Tsunami

Japan＇s first open sea offshore wind farm, Kamisu offshore windfarm Phase l, was stricken by an earthquake of intensity 6 on the Japanese seismic scale and a five-meter-high tsunami during the Great East Japan Earthquake on March 11,2011. The wind farm resumed operation on March 14 after checks revealed no damage to the system, even though the wind farm was temporarily forced to stop due to the grid failure caused by the earthquake. Wind turbines require a precise seismic design especially in an earthquake-prone country such as Japan. Wind power Kamisu Phase 2 was built one year after the earthquake based on the experience of Kamisu Phase 1. This paper presents the seismic design of offshore wind turbines and the situation during the earthquake and tsunami.     

2011年日本东北地区太平洋近海地震地基液化灾害综述

2011年3月11日,日本太平洋东海岸发生M_w 9.0级大地震,并引发巨大海啸,导致了日本东北和关东地区大面积的地基液化震害。通过现场震害调查和最新资料分析,首先较为系统地介绍了日本地震受灾区的液化宏观现象和典型震害特征。其次,研究了余震再液化和地震-海啸耦合灾害的破坏机制和特征,指出余震再液化受地震力大小、应力历史及超孔隙水压力消散程度的影响,并将地震和海啸耦合破坏过程分为3个阶段：震后液化阶段、间歇期恢复阶段、海啸流滑破坏阶段;最后,对此次强震中有关抗液化地基处理方法的有效性进行了分析与探讨,以期为今后的地基抗液化设计提供参考与借鉴。     

Thai adolescent survivors 1 year after the 2004 tsunami: A mixed methods study.

This study examined the impact of the 2004 Asian tsunami on 400 Thai adolescents 1 year after the disaster. Quantitative analyses showed that youth behavior problems were positively associated with tsunami experiences and negatively associated with positive family functioning. Tsunami exposure, school connectedness, religious beliefs and practices, and availability of mental health services did not predict behavior problems. Sequential regression analysis was performed with age, gender, tsunami experiences, and family functioning predicting youth behavior problems. In-depth interviews with 40 adolescents revealed many losses and difficulties after the tsunami, including death of parents and school difficulties. Positive aspects of recovery were support from family, peers, and other social networks and increased educational opportunities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behaviours of reinforced-concrete building under tsunami loading

The 26 December 2004 Indian Ocean tsunami caused damage to many buildings and killed a lot of people in several countries that border on the Indian Ocean including Thailand. To understand the behaviour of reinforced-concrete buildings under tsunami loads, a generic one-storey building has been developed from the average values of the structural indices of residential houses in southern Thailand. The generic building has been analysed to capture responses under tsunami hydrodynamic forces. At each inundation depth, the lateral force has been increased until collapse. From results, the resistance of the building was controlled by the shear failure of columns at inundation depths lower than 2.57 m. The lateral resistances controlled by the shear failure were about 258 kN. As the inundation depth increased, locations of loads moved higher and the flexural failure occurred in the columns of the building. At an inundation depth of 3.2 m, the lateral resistance decreased about 50% from that controlled by the shear failure.     

印度洋海啸与政府危机管理

文章从政府危机管理出发,分析了印度洋海啸造成众多人员伤亡和巨大财产损失的间接原因有危机发生前的监测预警不力,预防危机发生的准备不力,危机发生后的应对困难。并借鉴了英美日3国危机管理的经验,提出政府危机管理应重在建立危机的预警系统、建立国际沟通与多国合作的协调关系、建立健全政府危机管理的应急决策机制、建立社会力量的动员与参与机制、建立财政资源的动员机制、制定相应的法律法规、信息及时有效公开这7个方面着力。     

开阔海域越洋海啸波高计算的一种简化方法

该文研究了开阔海域中越洋海啸波高的简化计算方法。基于选取具有一系列断裂带长宽比的震源参数,采用Okada弹性变形理论生成初始海底变形,运用基于有限体积法的非线性浅水方程数值模型,模拟地震激发海啸在4 000 m水深的平底地形上的传播过程。通过监测布置在相对震源中心不同距离及方位角上测点的波面时间序列,研究海啸波高在不同距离及方位角上的分布规律,给出不同断裂带长宽比下越洋海啸传播过程中首波幅值的分布关系式;进一步分析了断裂带长宽比对模型参数的影响,得出了归一化的越洋海啸波高计算经验公式,并与日本2011年海啸实际记录进行对比,验证了该近似方法的有效性。     

Optimal Location of Deep-Sea Tsunami Detectors

The development of deep-sea detectors has significantly enhanced the potential for tsunami detection, particularly in the Pacific region. The detectors work in combination with satellite communication technology and surface communication buoys to provide an efficient and effective warning technology. The objective of this study is to identify the optimal distribution of a limited number of detectors, given that a maximum of six potential buoy sites has already been determined. Two objective functions are developed, one for a Pacific-wide warning potential, and the second a more specific USA warning potential. The resulting non-linear 0-1 integer-programming problems are readily solved using enumeration techniques.
The results conclude that three detectors in the Tsunami Warning System can achieve the maximum warning potential for both the Pacific region and the USA.     

Parallel tsunami simulation and visualization on tiled display wall using OpenGL Shading Language

Tsunami simulation consists of fluid dynamics, numerical computations, and visualization techniques. Nonlinear shallow water equations are often used to model the tsunami propagation. Tsunami inundation is modeled by adding the friction slope to the conservation of momentum. The two-step second-order finite difference MacCormack numerical method can solve these equations. It is well suited for nonlinear equations and simpler for related application development. In addition, the finite difference method can be computed in parallel. The programmable graphics hardware allows general-purpose computing on graphics processing units (GPUs) to solve the MacCormack method in parallel to speed up the simulation. Tsunami simulation data can be loaded as textures data in graphics memory, the computation processes can be written as shader programs using OpenGL Shading Language so that the operations can be computed by graphics processors in parallel. We developed different versions of the tsunami simulation and visualization programs: (i) CPU-based, and (ii) CPU–GPU collaboration to implement the MacCormack numerical method. The performance results showed that graphics hardware accelerated simulation had a significant improvement in the execution time of each computation step. Real-time simulation and visualization are made possible by the programmable shaders. Furthermore, we achieved high-performance parallel visualization on a tiled display wall with a cluster of computers.