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

卡斯卡迪亚巨型逆冲断层与北圣安德烈亚斯断层之间的应力传递

• 批准号: 0850931
• 负责人: Chris Goldfinger
• 金额: $ 44.5万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0850931&HistoricalAwards=false
• 关键词: Stress; Transfer; Between; Cascadia; Megathrust

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.

北美西海岸从加州湾到不列颠哥伦比亚省是一个地震活动频繁的地区。加州发生大地震是众所周知的。鲜为人知的是，加州最北端、华盛顿西部和俄勒冈州（卡斯卡迪亚边缘）经常发生真正巨大的“巨型逆冲断层”地震，最后一次地震发生在1700年左右。了解这些事件的频率以及卡斯卡迪亚事件与南部加州圣安德烈亚斯断层事件之间的任何联系至关重要。地震通常会在近海产生浊流（海底滑坡）沉积物。解决这些问题的一种方法是通过确定这些矿床的年代来建立年表。该项目将获取新的岩心，并对卡斯卡迪亚边缘沿着的浊流岩进行年代测定，以改进这一活跃边缘环境中的高分辨率古地震年表，并测试两个板块边界断层系统之间相互作用的拟议模型。长的古地震记录提供了进行这种比较的机会，测试重现模型，并建立行为和板块边界相互作用的长期记录，而这些记录通常太短的地震记录是不可能的。这项工作的主要目的是测试的假设，地震沿着卡斯卡迪亚边缘触发事件的北方圣安德烈亚斯断层在全新世反复。这项工作产生更广泛的影响，部分原因是卡斯卡迪亚边缘预计将产生真正巨大的“大推力”地震，伴随着海啸危险，这项工作具有巨大的社会意义。这项工作将对美国和加拿大的地震和海啸灾害评估产生重大的直接影响。其他好处是培训研究生和本科生参与该项目。