RAPID: Observations of Sediment Scour and Deposition in the Vicinity of Ports and Harbors from the 11 March 2011 Japan Tsunami

韦斯/113534/得克萨斯州A M 2011年3月11日9级日本地震引发了跨洋海啸，对整个太平洋造成了重大影响。虽然日本以外的海啸不是灾难性的，但局部地区有相当大的破坏，特别是在港口，海港和码头。港口周围的防护屏障，如防波堤，确实有效地减少了日常风浪的影响。然而，在海啸中，能量集中在这些屏障的缺口处，通常是港口入口通道。这种集中导致了极端的水流、湍流和大量的沉积物运输。本项目的主要目的是观察、记录和了解海啸对港口附近的水动力和沉积影响，并比较太平洋有人居住地区的海啸淹没特征。本项目支持对海啸进行跨学科的沿海影响调查，重点关注太平洋岛屿和其他选定的远场地点，以重建海啸特征。以及事件期间的沉积物动力学。工程评估和沉积研究在海港、港口和沿海基础设施内和附近联合进行，以提供对这一事件的全面评估。在基础设施附近，该团队确定助跑、淹没距离和水流深度。在工程评估过程中，该小组测量基础设施周围的冲刷情况（如果可以进入的话），并采访目击者，了解海啸到达的时间轴、洪水动力学以及海啸造成的港口、港湾和码头的流体动力学。与当地港务长和船长的讨论提供了有关水下冲刷和沉积的区域和严重程度的信息。在无人居住的地区或基础设施对海啸淹没动态影响最小的地区，该小组确定海啸破坏和洪水区特征，并将这些发现与沿海结构附近的数据进行比较。该小组还确定了海啸产生的沉积物或侵蚀的特征。对于矿床，他们测量范围、厚度、级配趋势，并取样进行粒度分析。如果土壤材料允许，他们会挖一条探沟来寻找过去海啸的沉积物。结合美国西海岸沿着的PI已经完成的调查，这份数据和观测资料的汇编是海啸影响现代海事基础设施（从小型游艇码头到大型商业港口）的最全面的资料汇编。这份跨学科的RAPID建议书将包括海啸破坏的工程表征以及洪水区，并对海啸沉积物和侵蚀进行调查。由于对人为和自然环境进行了更加连贯一致的评估，调查的跨学科性质有可能改变今后进行海啸实地调查的方式。沉积学研究还将从地球科学的角度对数据进行分析，从而更全面地描述海啸事件的特征，并可能考虑到古海啸记录。如果能够追溯地质历史，从沉积物中估计海啸强度和极端事件的复发，那么有效的灾害规划将产生巨大的影响。此外，对海啸在沿海基础设施附近输送和冲刷沉积物的能力有了一定的了解，我们应该能够更好地设计和减轻这些破坏性影响。

Weiss/113534/Texas A&MThe magnitude 9 March 11, 2011 Japanese earthquake spawned a trans-oceanic tsunami causing significant effects throughout the Pacific. While the tsunami outside of Japan was not catastrophic, there were localized pockets of considerable damage, particularly in ports, harbors, and marinas. Protective barriers around ports and harbors, such as breakwaters, do effectively reduce the effects of everyday wind waves. However, with tsunamis, the energy is focused at the gaps in these barriers, typically the harbor entrance channel. This focusing leads to extreme currents, turbulence, and significant sediment transport. It is the overarching theme of this proposal to observe, document, and understand the tsunami-driven hydrodynamic and sedimentological effects near ports and harbors and compare the tsunami inundation characteristics in inhabited areas throughout the Pacific.This grant supports an interdisciplinary, coastal impact survey of the tsunami that focuses on Pacific islands and other selected far field locations to reconstruct the tsunami characteristics, as well as sediment dynamics during the event. Engineering evaluation and sedimentary studies are jointly done in and near harbors, ports, and coastal infrastructure to provide a comprehensive assessment of this event. In the vicinity of infrastructure the team determines the runup, inundation distance, and flow depth. During the engineering evaluation, the team measures scouring around infrastructure, if accessible, and interviews eyewitnesses about the timeline of tsunami arrival, inundation dynamics, and the hydrodynamics in ports, harbors, and marinas as a consequence of the tsunami. Discussion with local harbormasters and captains provides information about regions and severity of underwater scour and deposition. In uninhabited areas or areas with minimum influence of infrastructure on the tsunami inundation dynamics, the team determines the tsunami damage and flood-zone characteristics and compares these finding with data near coastal structures. The team also determines the characteristics of generated deposits or erosion from the tsunami. For deposits they measure the extent, thickness, grading trends, and take samples for grain-size analysis. If the soil material permits, they dig an exploratory trench to look for deposits from past tsunamis.Combined with surveys already completed by the PIs along the US West coast, this compilation of data and observations is the most comprehensive for a tsunami affecting all scales of modern maritime infrastructure from small boat marinas to large commercial ports.This interdisciplinary RAPID proposal will incorporate engineering characterization of tsunami damage and the flood zone with investigations of the tsunami deposits and erosion. The interdisciplinary character of the survey has the potential to transform how reconnaissance tsunami field surveys will be carried out in the future due to a more coherent and consistent assessment of man-made and natural environments. Sedimentologic studies will also bring a geoscientific perspective to the data that will result in a more complete characterization of tsunami event, potentially taking the paleo-tsunami record into account. If the skill to look back into geologic history to estimate tsunami intensity and extreme-event recurrence from sediment deposits existed, the implications for efficient hazard planning are tremendous. Furthermore, with some knowledge of the capacity of a tsunami to transport and scour sediment near coastal infrastructure, we should be able to better design for and mitigate these damaging impacts.