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

克里斯蒂娜·杜拉博士获得了NSF EAR博士后奖学金，在洪堡州立大学开展研究和教育计划。这项调查将在空间和时间上扩大卡斯卡迪亚边缘地震事件引起的沉陷的分辨率。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模型来估计西海岸的下沉。这项研究将由三部分组成：(1)从华盛顿南部、俄勒冈州和加利福尼亚州北部海岸扩展区域现代硅藻数据集，以更好地描述一系列潮汐环境中硅藻的垂直分带。这些信息将被用来推断岩心中硅藻化石组合的生态位；(2)开发一个新的基于硅藻的计算模型，与以前的模型相比，它将把沉降量估计的误差减少约28%；以及(3)利用这些信息来了解沿卡斯卡迪亚俯冲带的地震的时空分布。教育计划将包括为K12学校编写教材，参加教师工作坊，创建与儿童书籍配套的在线海啸课程，并通过当地社区团体为社区开展外联活动。准确和准确地估计多个地震周期的同震下沉对于了解过去地震期间应变积累和释放的模式、时间和大小至关重要。杜拉博士将使用新的基于贝叶斯硅藻的传递函数来估计同震下沉，并改进现有基于有孔虫的传递函数的准确性。对跨越卡斯卡迪亚俯冲带600公里以上的四个地点的多个核心的同震下沉的新估计将用于描述和关联沿走向的地震，并区分过去2000-4000年间的破裂长度和地震震级。高精度的下沉估计将被纳入三维弹性错位模型，以产生更现实的(异质与分段)破裂模型，这将有助于改进未来的地震和海啸风险评估。使用现代硅藻数据集和应用新的基于贝叶斯硅藻的传递函数将大大提高卡斯卡迪亚同震沉降估计的准确性和精确度，从而推动基于微化石的定量技术的发展。

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.