Collaborative research: The generation of triggered tremor

合作研究：触发性震颤的产生

• 批准号: 0809993
• 负责人: John Vidale
• 金额: $ 15.09万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0809993&HistoricalAwards=false
• 关键词: Collaborative; research; generation; triggered; tremor

The investigators plan to address some fundamental issues behind non-volcanic tremor. Where does triggered tremors occur along the transform plate boundary in California, and elsewhere in the world? Are tremors preferentially triggered in a limited range of tectonic regimes? Why do the geothermal regions have many triggered earthquakes, but no apparent triggered tremors? Is there a stressing threshold for triggered tremors? Their initial survey has shown that only a few teleseismic earthquakes triggered tremors around the Parkfield section of the SAF, but the triggering threshold is still not clear. A systematic examination of surface waves of many earthquakes with different amplitudes and frequency content is needed. It is still not clear whether fluid flow induced by volumetric changes of Rayleigh waves, or transient shear stresses from Love waves is the most effective mechanism for tremor triggering. A systematic survey of tremors triggered by many teleseismic events will help to distinguish different triggering mechanisms. Are the triggered tremors the same phenomenon as the ambient (non-triggered) tremors and do they follow the new scaling relationship of slow earthquakes? Does slow slip and triggered earthquake accompany triggered tremors? Is there a constant background of tremor? The work will provide better understanding of fault slip, and would have a transformative impact for seismology, geodesy, geology, friction and rock mechanics, and perhaps more. A better understanding of tremor occurrence along the SAF system in California and elsewhere and its relation to slow slip events and occurrence of large earthquakes is directly relevant to seismic hazard mitigation. The research will involve the education of graduate students in both participating institutions, and will also involve undergraduate students.

研究人员计划解决非火山地震背后的一些基本问题。加利福尼亚和世界其他地方的转换板块边界沿线的哪些地方会发生引发的地震？地震是否优先在有限的构造区域范围内引发？为什么地热区多次引发地震，却没有明显的引发地震？触发性震颤是否存在压力阈值？他们的初步调查显示，只有少数远震地震引发了 SAF 帕克菲尔德地区周围的地震，但触发阈值仍不清楚。需要对具有不同振幅和频率内容的许多地震的表面波进行系统检查。目前尚不清楚瑞利波的体积变化引起的流体流动或洛夫波的瞬态剪切应力是否是触发震颤的最有效机制。对许多远震事件引发的震动进行系统调查将有助于区分不同的触发机制。触发的地震与周围（非触发）的地震是相同的现象吗？它们是否遵循慢地震的新尺度关系？慢滑移和触发地震是否伴随着触发地震？是否有持续的颤抖背景？这项工作将提供对断层滑移的更好理解，并对地震学、大地测量学、地质学、摩擦和岩石力学等产生变革性影响。更好地了解加利福尼亚州和其他地方的 SAF 系统发生的地震及其与慢滑动事件和大地震发生的关系，与减轻地震灾害直接相关。该研究将涉及两个参与机构的研究生教育，也将涉及本科生。