Towards a Comprehensive Understanding of Episodic Tremor and Slip

全面了解阵发性震颤和滑倒

• 批准号: 0710835
• 负责人: Gregory Beroza
• 金额: $ 27.98万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0710835&HistoricalAwards=false
• 关键词: Towards; Comprehensive; Understanding; Episodic; Tremor

In this research we develop and apply techniques to improve our understanding of a recently discovered phenomenon known as deep, non-volcanic tremor. Deep tremor is a more or less incessant, but weak, shaking of the ground that has been associated with large, but very slow earthquakes. The nature of tremor, with long, but not impulsive, episodes of ground motion requires new and innovative approaches from seismologists because the usual analysis applied to ordinary earthquakes cannot be applied to tremor. We are currently improving methods that have already been developed by the PI and his colleagues, and applying them to tremor in different areas. We are also continue to develop new and improved methods for tremor analysis. Among these are matched-filter analysis of low frequency earthquakes, a running auto-correlation analysis of tremor episodes to detect low frequency earthquakes, and a ''sub-space'' detection algorithm for identifying similar, but not identical small low frequency earthquakes. We use the understanding that emerges from this analysis to address the systematics of tremor behavior of the mechanics of the tremor process. The areas of the proposed study are all areas where tremor occurrence is well documented, specifically: Cascadia, Southwest Japan, and Central California. The strategic location of tremor -- at the boundary of the locked zone where we expect future large earthquakes to initiate -- and the emerging understanding that it represents shear slip on the plate boundary, makes this an important research target with significant potential implications for earthquake forecasting. In particular, an improved understanding should help scientists to assess the significance of deep tremor for earthquake hazard in the Cascadia subduction zone and in central California, where tremor is observed deep under the Cholame segment of the San Andreas Fault, a segment that has not ruptured in over 150 years. Another important broader impact is the international flavor of this work: U.S. researchers and graduate students will collaborate with researchers at the University of Tokyo, the National Institute for Earth Sciences and Disaster Prevention, and other institutions in Japan on significant portions of this research.

在这项研究中，我们开发并运用技术来提高我们对最近发现的现象，称为深，非volcanic震颤。 深度震颤或多或少是不断的，但弱的地面震动，与大地震相关，但地震却非常缓慢。 地面运动的震颤的性质（不长但不冲动）需要采用地震学家的新方法和创新的方法，因为应用于普通地震的通常分析不能应用于震颤。 目前，我们正在改进PI及其同事已经开发的方法，并将其应用于不同领域的震颤。 我们还将继续开发新的和改进的震颤分析方法。其中包括对低频地震的匹配过滤器分析，震颤发作以检测低频地震的运行自动相关分析，以及一种“子空间”检测算法，用于识别相似但相同的小低频地震。 我们利用从该分析中出现的理解来解决震颤过程力学的震颤行为的系统。 拟议的研究的领域是震颤发生的所有区域，尤其是：卡斯卡迪亚，西南日本和加利福尼亚中部。 震颤的战略位置 - 在锁定区域的边界处，我们期望将来会发生大地震 - 并且新兴的理解是它代表了板块边界上的剪切滑移，这使这是一个重要的研究目标，对地震具有重要的潜在影响预测。 特别是，提高的理解力应帮助科学家评估卡斯卡迪亚俯冲带和加利福尼亚州中部的深层震颤对地震危险的重要性，在圣安德烈亚斯断层的乔利亚郡段下，震颤被观察到了震颤，这一部分没有破裂在150多年的时间内。 另一个重要的广泛影响是这项工作的国际风味：美国的研究人员和研究生将与东京大学的研究人员，国家地球科学与灾难预防研究所以及日本的其他机构在这项研究的大部分研究中合作。