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

威斯/113534/德克萨斯A&A&M 2011年3月11日日本发生里氏9级地震，引发了一场横跨大洋的海啸，对整个太平洋地区造成了重大影响。虽然日本以外的海啸并不是灾难性的，但当地也有相当大的破坏，特别是在港口、港口和码头。港口和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，对于海啸，能量集中在这些屏障的缝隙上，通常是港口入口航道。这种聚焦导致了极端洋流、湍流和显著的泥沙输送。这项建议的首要主题是观察、记录和了解海啸对港口和港口附近的水动力和沉积学的影响，并比较整个太平洋有人居住地区的海啸淹没特征。这笔赠款支持对海啸进行跨学科的沿海影响调查，重点是太平洋岛屿和其他选定的远场位置，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港口、港口和沿海基础设施及其附近联合进行，以提供对这一事件的全面评估。在基础设施附近，团队确定梯级、淹没距离和水流深度。在工程评估期间，该小组测量了基础设施周围的冲刷情况(如果可以进入)，并就海啸到达的时间表、淹没动态以及海啸导致的港口、港口和码头的水动力问题采访了目击者。与当地港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，研究小组确定了海啸破坏和洪泛区特征，并将这些发现与沿海建筑物附近的数据进行了比较。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、分级趋势，并采集样本进行粒度分析。如果土壤物质允许，他们会挖一条勘探沟来寻找过去海啸的沉积物。结合美国西海岸PI已经完成的调查，这次数据和观测的汇编是影响从小船码头到大型商业港口的所有规模的现代海洋基础设施的最全面的海啸。这项跨学科的快速提案将把海啸破坏和洪泛区的工程特征与海啸沉积物和侵蚀的调查结合在一起。由于对人为和自然环境的评估更加连贯和一致，这项调查的跨学科性质有可能改变今后进行海啸实地勘察的方式。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，并有可能将古海啸记录考虑在内。如果存在回顾地质历史来估计海啸强度和来自沉积物的极端事件复发的技能，那么对有效的灾害规划的影响是巨大的。此外，对海啸输送和冲刷沿海基础设施附近沉积物的能力有了一些了解，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.