Remote Triggering Inside Versus Outside Geothermal Fields

地热田内部与外部的远程触发

• 批准号: 1447105
• 负责人: Guoqing Lin
• 金额: $ 10.18万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1447105&HistoricalAwards=false
• 关键词: Remote; Triggering; Inside; Versus; Outside

Remote triggering by large earthquakes at regional distances has been globally observed and intensely studied since the 1992 Mw 7.3 Landers earthquake in California. However, most of the previous studies were conducted at spatial scales of hundreds of kilometers and did not differentiate the actual operational geothermal fields with anthropogenic setting and their adjacent fault zones with natural setting. A two-year project is proposed for detailed analyses of the remotely triggered seismicity to examine hypothesis that geothermal fields respond differently from their vicinity to remote earthquakes due to the stress-state changes that are associated with the anthropogenic activity inside the geothermal field. The expected results will improve knowledge of the effect of pore fluid pressure on earthquake initiation and interaction and contribute to models of remotely triggered and induced seismicity, which will be important for evaluating the potential of future seismic hazards in geothermal fields due to remote earthquakes and human activity. In this proposed work, three operational geothermal fields under active tectonic settings in California corresponding to three large distant earthquakes are selected. The focus of this research is to compare different behaviors between each geothermal field (~10x10 km^2) and their adjacent fault zones (~100x100 km^2) that are split into several subareas. The results will address the following questions: (1) How does seismicity rate change inside and outside the geothermal fields responding to each remote earthquake? (2) How different are the stress fields inside and outside the geothermal fields? (3) How do shallow and deep earthquakes respond to remote triggering? (4) Is there any correlation between the net production rate and the seismicity rate inside the geothermal field? (5) What is the difference in the seismic velocity structure and in situ Vp/Vs inside and outside the geothermal fields?

自1992年MW 7.3 Landers地震以来，在全球范围内，在区域距离处发生大地震的远程触发。但是，以前的大多数研究都是在数百公里的空间尺度上进行的，并未以人为设置和自然环境区分实际的操作地热场及其相邻的断层区。提出了一个为期两年的项目，以详细分析远程触发的地震性，以检查地热场因与远程地震的响应方式不同，因为由于压力状态变化与地理热场内的人为活性相关。预期的结果将提高人们对孔隙流体压力对地震开始和相互作用的影响的了解，并有助于远程触发和诱发的地震性模型，这对于评估由于偏远地震和人类活动而导致地热场中未来地震危害的潜力至关重要。在这项拟议的工作中，在加利福尼亚的主动构造环境下进行了三个操作地热场，其中选择了与三个大远处地震相对应的。这项研究的重点是比较每个地热场（〜10x10 km^2）及其相邻断层区（〜100x100 km^2）之间的不同行为，这些区域分为几个亚地区。结果将解决以下问题：（1）地震速率在响应每个远程地震的地热场内外如何变化？ （2）地热场内部和外部的应力场有何不同？ （3）浅层和深层地震如何应对远程触发？ （4）净生产率与地热场内的地震速率之间是否存在任何相关性？ （5）地震速度结构以及地热场内外的原位VP/VP/与原位VP/VP有什么区别？