EAR-PF: Reconstructing land-level change throughout prehistoric megathrust earthquake cycles at the Cascadia subduction zone

EAR-PF：重建卡斯卡迪亚俯冲带史前巨型逆冲地震周期中的土地平面变化

• 批准号: 1952740
• 负责人: Isabel Hong
• 金额: $ 17.4万
• 依托单位: Hong, Isabel
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952740&HistoricalAwards=false
• 关键词: EAR; PF; Reconstructing; land; level

Dr. Isabel Hong has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at Simon Fraser University and Central Washington University to address key knowledge gaps that remain in our spatial and temporal understanding of the occurance of great earthquakes in the Cascadia subduction zone. Reconstructions of coastal land-level change using diatoms in new geographic locations and between great earthquakes will provide crucial estimates of previously unexplored regions and timescales. Dr. Hong will reconstruct a history of land-level change through time by identifying and mapping coastal sites with well-preserved geologic evidence of land-level change. A novel statistical model using present-day diatoms will be applied to fossil diatoms to provide quantitative estimates of land-level change with reduced uncertainty. These estimates will be integrated into datasets spanning both the United States and Canada to provide improved seismic hazards maps that span the entirety of the Cascadia subduction zone. The educational plan will provide opportunities for underrepresented undergraduate and graduate students to participate in field- and laboratory-based work. Samples collected from this investigation will be used to develop a coastal hazards curriculum.The accurate assessment of regional seismic hazards along the Cascadia subduction zone requires well-constrained estimates of tectonic plate deformation both during (coseismic) and in-between (interseismic) great earthquakes. Estimates of coastal land-level change derived from microfossil (e.g., diatoms) transfer functions within stratigraphic records are the most precise means to reconstruct deformation during past megathrust earthquakes. However, the application of a diatom transfer function has been limited at Cascadia by the absence of modern analogues for fossil assemblages, which has led to unreliable estimates of land-level change. To address this limitation, Dr. Hong uses a new and unique approach of grouping diatom species with similar distributions across elevation that will reduce the dissimilarity between fossil and modern samples. The grouped species will be used to develop a new Bayesian diatom transfer function to reconstruct land-level change through entire earthquake cycles with reduced uncertainty. Broader impacts of this project include training undergraduate and graduate students in areas of Paleoseismology. The results of this work will help improve current seismic hazard maps in the Pacific Northwest. This project also received funding from the Tectonics and the Marine Geology and Geophysics programs.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.

伊莎贝尔·洪（Isabel Hong）博士已获得NSF耳朵博士后研究金，以在西蒙·弗雷泽大学（Simon Fraser University）和中央华​​盛顿大学（Central Washington University）进行研究和教育计划，以解决我们对卡斯卡迪亚俯卧toctauction区大地震发生的空间和时间理解的关键知识差距。在新地理位置和大地震之间使用硅藻对沿海地面变化的重建将提供对以前未开发的地区和时间尺度的关键估计。 Hong博士将通过确定和绘制沿海地区的地质变化的地质证据来重建土地层次变化的历史。使用当前硅藻的新型统计模型将应用于化石硅藻，以降低不确定性，对土地水平变化进行定量估计。这些估计将集成到跨越美国和加拿大的数据集中，以提供跨越整个卡斯卡迪亚俯冲带的改进的地震危险图。该教育计划将为代表性不足的本科生和研究生提供机会参加基于现场和实验室的工作。从这项研究中收集的样品将用于开发沿海危害课程。对卡斯卡迪亚俯冲带沿线的区域地震危害的准确评估需要对构造板板变形（coseismiscic）和内部（siessismisic）巨大地震的构造板变形的估计。地层记录中微化石（例如，硅藻）转移功能得出的沿海地位变化的估计是在过去的大型地震中重建变形的最精确手段。但是，由于缺乏化石组合的现代类似物，在卡斯卡迪亚的硅藻传递功能的应用受到限制，这导致了对土地水平变化的不可靠估计。为了解决这一局限性，洪博士使用一种新的独特方法，将硅藻物种分配具有相似分布的高度分布，这将减少化石和现代样品之间的差异。分组的物种将用于开发新的贝叶斯硅藻转移功能，以通过整个地震周期降低不确定性来重建土地水平变化。该项目的更广泛影响包括培训古学学领域的本科生和研究生。这项工作的结果将有助于改善西北太平洋地区当前的地震危险图。 该项目还从构造学和海洋地质与地球物理学计划中获得了资金。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准通过评估来支持的。

项目成果

Diatoms of the intertidal environments of Willapa Bay, Washington, USA as a sea-level indicator

• DOI: 10.1016/j.marmicro.2021.102033
• 发表时间: 2021-07
• 期刊: Marine Micropaleontology
• 影响因子: 1.9
• 作者: I. Hong;B. Horton;A. Hawkes;R. O'Donnell;J. Padgett;T. Dura;S. Engelhart