RAPID: Recording Tsunami Impacts from the Taan Fjord, Alaska Landslide of October 17th, 2015

2015年10月17日，北美洲几十年来最大的山体滑坡发生在阿拉斯加东南部冰湾的支流塔安峡湾。山体滑坡引发了当地巨大的海啸。卫星图像的流量指标显示，紧邻滑坡体的最大海啸上升幅度超过190米。这样的最大累积将仅次于1958年Lituya湾滑坡造成的最大累积，这是一个记录不佳（以现代标准衡量）的事件，尽管如此，它仍然是工程界了解极端滑坡海啸危害的最重要数据集。该项目支持对塔安峡湾滑坡引发的海啸进行跨学科的沿海影响调查。调查的目的是记录整个塔安峡湾和冰湾的累积测量和海啸影响。在减轻灾害方面，海啸行为的记录至关重要，有助于解决许多问题，例如：基础设施要离潜在的滑坡有多远，就像在加拿大西部和阿拉斯加提议的那样，液化天然气（LNG）设施离滑坡源有多近，对现有的码头、港口和经常经过峡湾系统的许多游轮的危害如何？要记录的数据对于正确说明滑坡源及其引发海啸的可能性至关重要。从初步的模拟和早期的侦察旅行来看，我们预计海啸的上升高度将超过100米，海啸在穿过和离开塔安峡湾时，波浪高度会有一个逐渐但非常局部的衰减。由于极端的上升和淹没距离，以及偏远的位置，团队将使用高精度实时动态（RTK）测量系统，我们预计在数据进行潮汐校正后，该系统将产生10厘米精度的位置高程。要收集的数据类型包括最重要的上升高度、水流深度剖面、沉积物冲刷和沉积区域、碎屑堆以及海啸对各种植被的影响。这项调查的数据一旦处理完毕，将免费提供给工程界的所有成员。特别是，Lynett参与了西部各州的海啸灾害测绘，他参与了国家海啸减灾计划（NTHMP），以及与其他研究滑坡海啸的人的现有合作表明，这些数据将立即纳入正在进行的灾害研究。

On October 17th, 2015, the largest landslide in North America in decades occurred in Taan Fjord, an arm of southeast Alaska's Icy Bay. The landslide triggered an enormous local tsunami. Flow indicators from satellite imagery suggest that the maximum tsunami runup immediately adjacent to the slide mass exceeds 190 m. Such a maximum runup would be second only to that created by the 1958 Lituya Bay landslide, a poorly recorded (by modern standards) event that is nonetheless the most important dataset for understanding extreme landslide tsunami hazards available to the engineering community. This project supports an interdisciplinary, coastal impact investigation of the tsunami generated by the Taan Fjord landslide. The aim of survey is to record runup measurements and tsunami impacts throughout Taan Fjord and Icy Bay. In the context of hazard mitigation, a record of the tsunami behavior is of paramount importance, and would assist in resolving many questions, for example: How far away from potential landslides does infrastructure need to be located How close can liquefied natural gas (LNG) facilities, as are being proposed throughout western Canada and Alaska, be to landslide sources What about the hazard to existing marinas, harbors, and ports, and the many cruise ships that regularly travel through fjord systems The data to be recorded will be essential to the proper specification of the landslide source and its tsunamigenic potential.From preliminary simulations and early reconnaissance trips, we expect there to be widespread areas where the tsunami runup exceeds 100 meters in elevation, with a gradual, but very localized attenuation of wave height as the tsunami traveled through and out of Taan Fjord. Owing to the extreme runup and inundation distances, as well as the remote location, the team will use a high-accuracy Real Time Kinematic (RTK) survey system, which we expect will yield 10-cm accuracy location elevations, after the data is tide-corrected. The types of data to be collected include the most-important runup elevations, flow depth profiles, areas of sediment scour and deposition, debris piles, and the impact of the tsunami on various types of vegetation. The data from this survey, once processed, will be provided freely to all members of the engineering community. In particular, Lynett's involvement with tsunami hazard mapping in western States, his participation in the National Tsunami Hazard Mitigation Program (NTHMP), and existing collaborations with others studying landslide tsunamis indicates that this data will be folded into ongoing hazard studies immediately.