Stress Transfer Between the Cascadia Megathrust and the Northern San Andreas Fault

从加利福尼亚州海湾到不列颠哥伦比亚省的北美西海岸以高地震活动为特征。加州发生大地震是众所周知的。不太为人所知的是，加利福尼亚州最北部、华盛顿州西部和俄勒冈州(卡斯卡迪亚边缘)经常发生真正意义上的大地震，最近一次发生在大约1700年。了解这些事件的频率，以及卡斯卡迪亚事件与加利福尼亚州圣安德烈亚斯断层以南发生的事件之间的任何联系是至关重要的。地震通常会产生近海的浊积物(海底滑坡)。解决这些问题的一种方法是通过测定这些矿床的年代来建立年表。该项目将沿着卡斯卡迪亚边缘获取新的岩芯和浊积岩日期，以改进在这种活动边缘环境下的高分辨率古地震年代学，并测试提出的两个板块边界断层系统之间相互作用的模型。长的古地震记录提供了进行这种比较的机会，测试了复发模型，并建立了行为和板块边界相互作用的长期记录，这与通常太短的地震记录是不可能的。这项工作的主要目的是检验这样一个假设，即卡斯卡迪亚边缘的地震在全新世期间反复触发了圣安德烈亚斯北部断层上的事件。这项工作产生更广泛影响的部分原因是，卡斯卡迪亚边缘地区预计会发生真正的“大地震”，并伴随着海啸灾害，这项工作具有巨大的社会意义。这项工作应该会对美国和加拿大的地震和海啸风险评估产生重大的、直接的影响。其他好处包括培养研究生和本科生参与该项目。

The west coast of the North America from the Gulf of California to British Columbia is characterized by high earthquake activity. That great earthquakes occur in California is well known. Less well known is the fact that northernmost California, and western Washington and Oregon (the Cascadia Margin) are subject to truly great, "megathrust" earthquakes, the last of which occurred in about 1700. It is of vital importance to understand both the frequency of these events, and any linkage between events in Cascadia and those that occur to the south, on the San Andreas Fault in California. Earthquakes commonly produce turbidite (submarine landslide) deposits offshore. One way to address these issues is to establish chronologies by dating these deposits. This project will acquire new cores and date turbidites along the Cascadia Margin to improve high-resolution paleoseismic chronologies in this active margin setting and test a proposed model of interaction between two plate boundary fault systems. Long paleoseismic records afford the opportunity to make such comparisons, test models of recurrence, and establish long term records of behavior and plate boundary interaction that are not possible with earthquake records that are typically much too short. A primary aim of this work is to test the hypothesis that earthquakes along the Cascadia Margin have triggered events on the Northern San Andreas Fault repeatedly during the Holocene. Broader impacts of this work arise in part from the fact that the Cascadia Margin is expected to produce truly great "megathrust" earthquakes, with attendant tsunami hazards, this work has enormous societal relevance. This work should have a major, direct impact on the assessment of earthquake and tsunami hazards in the U.S. and Canada. Other benefits are training graduate students and the involvement of undergraduates in the project.