EAR-PF: SPATIAL AND TEMPORAL VARIABILITY OF COSEISMIC SUBSIDENCE ALONG THE CASCADIA SUBDUCTION ZONE

EAR-PF：卡斯卡迪亚俯冲带同震沉降的时空变化

• 批准号: 1624795
• 负责人: Tina Dura
• 金额: $ 8.7万
• 依托单位: Dura Cristina
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1624795&HistoricalAwards=false
• 关键词: EAR; PF; SPATIAL; TEMPORAL; VARIABILITY

Dr. Cristina Dura has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at Humboldt State University. This investigation will expand the resolution of subsidence due to seismic events along the Cascadian margin in both space and time. This information is critical for the assessment of seismic and tsunami hazards along the Pacific coast in the USA. Dr. Dura will use computer modeling based on diatom abundance to estimate subsidence along the West Coast. The study will consist of three components: (1) expand regional modern diatom dataset from the coasts of southern Washington, Oregon, and northern California to better characterize the vertical zonation of diatoms in a range of tidal environments. This information will be used to infer ecological niches of fossil diatom assemblages in cores; (2) develop a new diatom-based computational model that will reduce errors on subsidence estimates by ~28% compared to previous models; and (3) use this information to understand the spatial and temporal distribution of earthquakes along the Cascadia subduction zone. The education plan will entail developing teaching materials for K12 schools, participating in teacher workshops, creating an online tsunami curriculum to accompany a children's book, and outreach events for the community through local community groups.Accurate and precise estimates of coseismic subsidence over multiple earthquake cycles are critical to understanding the patterns, timing, and magnitude of strain accumulation and release during past earthquakes. Dr. Dura will employ new Bayesian diatom-based transfer functions to estimate coseismic subsidence, and improve upon the accuracy of existing foraminifera-based transfer functions. New estimates of coseismic subsidence in multiple cores at four sites spanning over 600 km of the Cascadia subduction zone will be used to characterize and correlate earthquakes along strike and distinguish rupture lengths and earthquake magnitudes over the past 2000-4000 years. The high-precision subsidence estimates will be incorporated into 3-D elastic dislocation models to produce more realistic (heterogeneous vs. segmented) rupture models that will help improve future earthquake and tsunami hazard assessments. Using a modern diatom dataset and application of a new Bayesian diatom-based transfer function will advance quantitative microfossil-based techniques by significantly increasing the accuracy and precision of coseismic subsidence estimates at Cascadia.

Cristina Dura博士获得美国国家科学基金会EAR博士后奖学金，在洪堡州立大学开展研究和教育计划。这项研究将在空间和时间上扩大喀斯喀特边缘地震事件引起的沉降的分辨率。这些信息对于评估美国太平洋沿岸的地震和海啸灾害至关重要。杜拉博士将使用基于硅藻丰度的计算机建模来估计西海岸的沉降。该研究将由三个部分组成：(1)扩展来自华盛顿州南部、俄勒冈州和加利福尼亚州北部海岸的区域现代硅藻数据集，以更好地表征一系列潮汐环境中硅藻的垂直分带。这些信息将用于推断岩心中硅藻化石组合的生态位；(2)开发了一种新的硅藻计算模型，与以前的模型相比，该模型可将沉降估计误差降低约28%；(3)利用这些信息了解卡斯卡迪亚俯冲带地震的时空分布。该教育计划将包括为K12学校编写教材，参与教师讲习班，创建在线海啸课程以配合儿童书籍，以及通过当地社区团体为社区开展外展活动。准确和精确地估计多个地震周期的同震沉降对于理解过去地震中应变积累和释放的模式、时间和强度至关重要。Dura博士将采用新的基于贝叶斯硅藻的传递函数来估计同震沉降，并提高现有基于有孔虫的传递函数的准确性。在Cascadia俯冲带跨越600公里的四个地点的多个岩心的同震沉降的新估计将用于描述和关联过去2000-4000年间沿走向发生的地震，并区分破裂长度和地震震级。高精度的沉降估计将被整合到三维弹性位错模型中，以产生更真实的（非均匀的与分段的）破裂模型，这将有助于改进未来的地震和海啸危害评估。使用现代硅藻数据集和应用新的贝叶斯硅藻传递函数将通过显著提高卡斯卡迪亚同震沉降估计的准确性和精度，推进定量微化石技术。