Tsunamis: Landslide Generated Waves and Run-up and Landward Inundation

9523414雷克伦这个项目涉及与海啸造成的破坏有关的两个领域，即海啸的产生和沿海影响。海啸是由发生在海底的地震、山体滑坡和火山喷发等脉冲事件产生的海浪。海啸问题大致可分为三个方面：产生、传播和海岸效应。这项调查旨在减轻主要由近岸水下山体滑坡引起的海啸危险。在加利福尼亚州，许多海底峡谷垂直于海岸，峡谷头部靠近海岸，这些峡谷近岸地区储存的沉淀层在水下滑动可能会产生巨浪。造成这种滑坡的一个重要机制可能是远距离或近海地震，例如1994年1月的北岭地震，它在距离震中约20英里的圣莫尼卡沿海社区造成了相当大的震动和破坏。如果这种震动引发了近岸峡谷沉积层的崩塌，那么近岸水域就有可能产生破坏性的海啸。水下滑坡产生的波浪的形状和运动特性，以及它们在海岸和陆地传播时的变化，对于确定可能处于这种潜在破坏性波浪路径上的海堤和建筑物等建筑物的作用力很重要。该项目涉及通过水下沉淀物滑动了解海啸产生机制的实验，同时开发产生机制的分析模型。它将提供数据，帮助评估淹没距离，预测沿海洪水，并建议可靠的疏散区域界限。这些数据对工程设计、城市规划和改进海啸预警系统都很重要。这些结果也将直接适用于与其他波浪-结构相互作用有关的工程问题，如长波风暴波的岸上传播，以及内陆水库和海岸滑坡产生的波浪。***

9523414 Raichlen This project addresses two areas related to the damage resulting from tsunamis, namely generation and coastal effects. Tsunamis are ocean waves which are generated by impulsive events such as earthquakes, landslides, and volcanic eruptions occurring on the ocean bottom. The tsunami problem can be divided into three general areas: generation, propagation and coastal effects. This investigation is directed toward mitigation of the tsunami hazard primarily due to nearshore underwater landslides. In California, numerous submarine canyons are oriented perpendicular to the shore, with the canyon heads nearshore where the underwater sliding of sediment layers stored in the nearshore regions of these canyons could generate large waves. An important mechanism which could cause such landslides could be a distant or an offshore earthquake, such as the Northridge earthquake of January 1994 which caused considerable shaking and damage in the coastal community of Santa Monica, approximately 20 miles from the epicenter. If such shaking had triggered the failure of sediment layers in the nearshore canyons, it is possible that a damaging tsunami could have been generated in the nearshore waters. The shape and the kinematic properties of waves generated by underwater landslides and their modification as they propagate shoreward and overland are important in defining the forces on structures, such as seawalls and buildings which may be in the path of such potentially-destructive waves. The project involves experiments to understand the tsunami generation mechanism through underwater sediment slides, in conjunction with the development of an analytical model for the generation mechanism. It will provide data to assist in the evaluation of inundation distances to predict coastal flooding, and suggest reliable limits to evacuation zones. Such data are important for the engineering design, urban planning, and for improvement of the tsunami warning syste m. The results will be directly applicable also to engineering problems associated with other wave-structure interactions, such as the shoreward propagation of long-wavelength storm waves, and to waves generated in inland reservoirs and coastal inlets by landslides. ***