RAPID: Characterizing Inundation and Sediment Transport Associated with Hurricane Michael: A Modern Analog for Paleo-Hurricane Reconstructions

目前的努力，以了解负责调制飓风活动的驱动机制显着阻碍了飓风发生的短仪器记录。基于沉积在沿海池塘和沼泽中的过洗层的代理记录提供了一种扩展我们对数千年前飓风袭击的知识的手段。这些古记录使我们能够阐明飓风活动的千年和百年尺度模式，并探索驱动飓风活动变化的机制。其中几个重建已经从佛罗里达的狭长地带发展起来，并将我们对该地区飓风活动的了解追溯到4000多年前。然而，需要有据可查的现代类似物来帮助解释长期记录。2018年10月，飓风迈克尔在佛罗里达的狭长地带登陆，这为研究与4类罢工相关的过洗沉积物的特征提供了机会。这项研究将检查沉积和景观变化在三个沿海天坑池塘的秃头点，佛罗里达，一个位置，约100公里的中心，飓风迈克尔上岸。这项工作将使用高程数据和取自池塘的新沉积物岩心的材料，并将此信息与来自同一池塘的先前研究的长期沉积学记录的结果进行比较。这项研究的结果将有助于限制在过去几千年中在该地区留下沉积物的史前事件的特征。 这项工作的更广泛影响包括增加联邦灾害机构、保险公司、沿海管理人员和社区对佛罗里达狭长地带发生大风暴的概率和时间的了解，这将有助于更好地进行土地和灾害规划。影响还包括研究生培训和通过讲座和与社区领袖的对话进行公众宣传。后一种外联活动对项目媒体报道具有很大的潜力。由于这些强风暴事件在时间和空间上的仪器记录有限，目前对飓风活动在数十年和更长时间尺度上的变化驱动因素的了解还不够。地质代理，如保存在沿海沉积环境中的过洗层，提供了一个重要的工具，研究飓风的变化在史前。这项研究涉及收集无人机空中数据和土地调查，以审查风暴及其风暴潮造成的地貌和海拔变化。它还涉及收集位于墨西哥海滩100公里内的佛罗里达狭长地带的秃头上的沉积物岩心，飓风迈克尔的眼睛于2018年10月登陆。沉积物采样和调查将在三个沿海天坑池塘进行，以前已经研究过：小塔克，鲻鱼，猎枪。本研究收集的数据将与这三个地点的基线数据进行比较，其中一些数据包括2010年进行的激光雷达（光探测和测距）飞机高程调查。将采集迈克尔飓风沉积物岩心，并对样品进行粒度、事件床沉积和碎屑成分检查。他们还将被检查的微体化石的测试，如有孔虫，从海底撕裂。后者的数据将有助于深入了解风暴期间海底波浪/潮汐侵蚀和海洋沉积物迁移的程度和力量。需要解决的问题包括：风暴强度和如何在地质记录中记录，以及风暴需要多接近一个地点才能导致事件床沉积。对现代类似物的研究，如飓风迈克尔留下的沉积物，对于能够正确解释这个和其他地方的沉积物记录至关重要。它还将提供该地区强风暴事件的长期重建以及可能更广泛适用的调查结果和协议。通过表征淹没水平和沉积物输送到三个目标研究地点的程度，该项目将能够更好地解释过去4000年来沉积在佛罗里达狭长地带的强飓风/风暴事件的性质。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Current efforts to understand the driving mechanisms responsible for modulating hurricane activity are significantly hampered by a short instrumental record of hurricane occurrence. Proxy records based on overwash layers deposited in coastal ponds and marshes provide a means of extending our knowledge of hurricane strikes back thousands of years. These paleo-records allow us to elucidate millennial and centennial scale patterns in hurricane activity and explore the mechanisms that drive changes in hurricane activity. Several of these reconstructions have been developed from the Panhandle of Florida and have extended our knowledge of hurricane activity in the area back more than 4000 years. However, well documented modern analogs are needed to help interpret the long term records. The landfall of Hurricane Michael on the panhandle of Florida in October 2018 provided an opportunity to investigate the character of overwash deposits associated with a category 4 strike. This research will examine sedimentological and landscape changes at three coastal sinkhole ponds on Bald Point, Florida, a location that is about 100 km from the center of where Hurricane Michael came ashore. The work will use elevation data and material from new sediment cores, taken from the ponds, and compare this information to results from longer term sedimentological records of previous studies from the same ponds. Results of this research will help constrain the character of prehistoric events that left deposits in the region over the past several millennia. Broader impacts of the work include increasing knowledge for use by federal disaster agencies, insurance companies, coastal managers, and communities about the probability and timing of major storm strikes on the Florida panhandle which should assist in better land and disaster planning. Impacts also include graduate student training and public outreach via lectures and conversations with community leaders. The latter outreach has strong potential for project media coverage.There is presently an insufficient understanding of what drives variability of hurricane activity on multidecadal and longer timescales due to the limited, in time and space, instrumental record of these strong storm events. Geologic proxies such as overwash layers preserved in coastal depositional settings provide an essential tool for examining hurricane variability in prehistory. This research involves the collection of drone-based aerial data and land surveys to examine geomorphic and elevation changes resulting from the storm and its storm surge. It also involves the collection of sediment cores on Bald Point on the Florida panhandle within 100 km of Mexico Beach where the eye of Hurricane Michael came ashore in October of 2018. Sediment sampling and surveys will be carried out at three coastal sinkhole ponds that have been previously studied: Little Tucker, Mullet, and Shotgun. Data collected in this study will be compared with the baseline data from these three sites, some of which includes LIDAR (LIght Detecting and Ranging) aircraft elevation surveys taken in 2010. Hurricane Michael sediment cores will be taken and samples will be examined for grain size, event-bed deposition, and clast composition. They will also be examined for the tests of microfossils, like foraminifera, ripped from the seabed. The latter data will provide insights into the extent and force of seabed wave/tide erosion and marine sediment transport during the storm. Questions to be addressed include: storm intensity and how that is recorded in the geological record and how close a storm needs to come to a site to result in event-bed deposition. Studies of modern analogs, such as the deposits left behind by Hurricane Michael, are essential for being able to correctly interpret the sediment record at this and other localities . It will also provide long-term reconstruction of strong storm events in the area and findings and protocols that may be applicable more widely. By characterizing the level of inundation and degree of sediment transport to the three targeted study sites, the project will be able to better interpret the nature of strong hurricane/storm events deposited over the last 4 millennia on the Florida panhandle.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.