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

Cristina Dura博士已获得NSF博士后奖学金，在洪堡州立大学开展研究和教育计划。这项调查将扩大由于地震事件沿着卡斯卡迪亚边缘在空间和时间上的沉降的分辨率。这些信息对于美国太平洋沿岸沿着地震和海啸灾害的评估至关重要。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沿着的沉降。该研究将包括三个组成部分：（1）扩大区域现代硅藻数据集从南部华盛顿，俄勒冈州，和北方加州海岸，以更好地表征硅藻的垂直地带性在一系列的潮汐环境。这些信息将用于推断岩心中化石硅藻组合的生态位;（2）开发一种新的基于生物统计学的计算模型，与以前的模型相比，该模型将减少沉降估计的误差约28%;（3）使用这些信息来了解卡斯卡迪亚俯冲带沿着地震的时空分布。该教育计划将包括为K12学校编写教材，参加教师研讨会，创建一个在线海啸课程，以配合儿童书籍，并通过当地社区团体为社区开展外联活动。准确和精确地估计多个地震周期的同震沉降对于了解过去地震期间应变积累和释放的模式，时间和幅度至关重要。 Dura博士将采用新的基于贝叶斯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精度。在卡斯卡迪亚俯冲带跨越600多公里的四个地点的多个岩芯中，对同震沉降的新估计将用于描述和关联沿着走向的地震，并区分过去2000-4000年的破裂长度和地震震级。高精度的沉降估计将被纳入三维弹性位错模型，以产生更现实的（异质与分段）破裂模型，这将有助于改善未来的地震和海啸危险评估。使用现代硅藻数据集和应用新的贝叶斯转换函数将通过显着提高卡斯卡迪亚同震沉降估计的准确性和精度来推进基于微体化石的定量技术。

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.