RAPID: Reconnaissance of Twin Landslides and Tsunami of 17 June 2017 in Greenland

2017年6月17日，由山体滑坡引发的海啸影响了格陵兰岛西部北部的一个大型峡湾系统。这项快速反应研究（Rapid）拨款支持美国参与对滑坡和海啸的双重侦察调查。该小组将与格陵兰政府协调侦察活动，并遵循极端地质事件勘测和国际海啸调查队（教科文组织）的规程。这一事件代表了一个独特的研究机会，因为两个相邻的滑坡活动不同的结果。两次滑坡的东部向卡拉特峡湾俯冲了1公里，并在乌曼纳克峡湾系统引发了海啸。山体滑坡引发的海啸将4名遇难者和几座房屋冲进了距离山体滑坡发生地约30公里的努加茨亚克峡湾。Nuugaatsiaq和Illorsuit的目击者用视频记录了海啸的淹没情况。活跃的西部滑坡以后陡坡和大裂缝为特征，因此在卡拉特峡湾仍然是一个危险，并导致一些当地村庄的长期疏散。该合同支持的侦察调查小组将收集卡拉特峡湾滑坡、悬崖和碎片雪崩轨迹的高质量倾斜航空摄影测量（OAP），以及地面海啸淹没测量。实地观测将使研究界推断出不同滑坡和海啸模型的预测能力。海啸目击者的视频将在现场进行校准，以提取水流深度和速度的时间序列。获得的现场数据将与过去实验项目收集的现有实验室滑坡海啸数据进行密切分析。该项目的主要成果将是一个综合的多尺度、地理参考数据库，其中包含滑坡参数、海啸破坏和洪泛区特征，并结合数值模型结果。将在接受调查的原居村庄和采访的目击者进行教育和外联讲座和简报。格陵兰岛山体滑坡引发的海啸凸显了不常遭受地震引发的海啸的沿海社区所面临的危险。在重大自然和人为事件之后进行灾后侦察，对这些事件的特征以及遭受这些灾难性事件的自然和人为基础设施的性能产生了重要的新见解。进行这些协调良好、执行良好的滑坡来源和海啸侦察活动的好处包括及早收集易腐烂的数据和建立多因素信息数据库，这些数据库为详细的长期后续调查和主要基于模型的调查奠定了基础。通过这项研究，研究人员可能能够理解夏至几天内北极地区4人的不寻常死亡人数。这一事件代表了一个独特的机会，因为一个山体滑坡陷入了卡拉特峡湾，而另一个邻近的山体滑坡仍然是一个活跃的危险。这将导致对一次滑坡引发的海啸进行灾后观测，并可能在灾前获得第二次滑坡引发的海啸的基线数据。这两个滑坡的体积将用倾斜航空摄影测量（OAP）来估计。泥石流体积沿“Sturzbahn”向下扩展将提供与物理模型中颗粒状滑坡扩展相比的滑坡基准。历史海啸的海啸来源和震级将根据最近的滑坡和冰川事件重新审视。收集高质量的洪水测量数据将使公众能够推断不同模型的预测能力，并评估它们在洪水绘图和业务预测方面的潜在用途。本研究产生的数据集和分析工具将在nsf支持的NHERI DesignSafe-CI.org门户网站上提供。这项研究将为地方当局提供重要信息，因为他们正在考虑建立滑坡监测和海啸预警系统，或永久重新安置撤离的村庄。它还将为参与侦察的美国学生提供重要的国际经验。

A 17 June 2017 landslide-generated tsunami impacted a large fjord system in the northern part of western Greenland. This Grants for Rapid Response Research (RAPID) award supports the US participation in the reconnaissance survey of the twin landslides and tsunami. The team will coordinate the reconnaissance activities with the Government of Greenland, and follow protocols of the Geotechnical Extreme Events Reconnaissance (GEER) and the International Tsunami Survey Team (UNESCO). This event represents a unique research opportunity since two adjacent landslides were active with different outcomes. The eastern of the two landslides plunged 1 km into the Karrat Fjord and generated a tsunami in the Uummannaq fjord system. The landslide-generated tsunami washed 4 victims and several houses into the fjord at Nuugaatsiaq, about 30 km from the landslide. Eyewitnesses at Nuugaatsiaq and Illorsuit recorded the tsunami inundation on video. The active western landslide features a back scarp and large cracks, and therefore remains a hazard in Karrat Fjord, and has led to extended evacuations of a few native villages. The reconnaissance survey team supported on this award will collect high quality oblique aerial photogrammetry (OAP) of the landslide, scarp, and debris avalanche track as well as ground based tsunami inundation measurements in Karrat Fjord. The field observations will allow the research community to infer the predictive capability of different landslide and tsunami models. Tsunami eyewitness videos will be calibrated in situ to extract time series of flow depth and velocity. The obtained field data will be analyzed closely with the existing laboratory landslide tsunami data collected by past experimental projects. The primary project deliverable will be a comprehensive multi-scale, geo-referenced database of landslide parameters, tsunami damage, and flood zone characteristics combined with numerical model results. Education and outreach lectures and briefings will be given at native villages surveyed and to eyewitnesses interviewed. The Greenland landslide-generated tsunami highlights coastal hazards to communities not commonly exposed to earthquake generated tsunamis.Post disaster reconnaissance following major natural and man-induced events has yielded significant new insights into both the characteristics of the events and the performance of natural and man-made infrastructure subjected to these catastrophic events. The benefits of conducting these well-coordinated, well-executed landslide source and tsunami reconnaissance activities include early collection of perishable data and the establishment of multi-factor databases of information that form the basis for detailed long-term follow-on and mostly modeling based investigations. Through this study, researchers may be able to understand the unusual death toll of 4 people in the Arctic within days of the summer solstice. This event represents a unique opportunity as one landslide plunged into Karrat Fjord, while another neighboring one remains an active hazard. This will lead to post disaster observations of one landslide generated tsunami and potentially before disaster baseline data of a second one. Both landslide volumes will be estimated with oblique aerial photogrammetry (OAP). The spreading of the debris avalanche volume down the "Sturzbahn" will provide a landslide benchmark in comparison with the granular landslide spreading in physical models. The tsunami sources and magnitudes of historic tsunamis will be revisited in light of recent landslide and glaciological events. Collecting high quality inundation measurements will allow the community to infer the predictive capability of different models and evaluate their potential uses for inundation mapping and operational forecasts. Datasets and analytical tools generated by this research will be made available on the NSF-supported NHERI DesignSafe-CI.org web portal. This study will provide important information to local authorities as they are considering landslide monitoring and tsunami warning systems or permanent relocation of the evacuated villages. It will also provide a significant international experience for the U.S. students involved in the reconnaissance.