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 年加利福尼亚州发生 7.3 级兰德斯地震以来，全球范围内都对区域性大地震的远程触发进行了观测和深入研究。然而，以往的研究大多在数百公里的空间尺度上进行，并没有区分实际运行的地热田与人为环境及其邻近断裂带与自然环境。提出了一个为期两年的项目，对远程触发的地震活动进行详细分析，以检验以下假设：由于与地热场内的人为活动相关的应力状态变化，地热场对远程地震的响应与其附近地区不同。预期结果将提高对孔隙流体压力对地震引发和相互作用的影响的认识，并有助于建立远程触发和诱发地震活动模型，这对于评估远程地震和人类活动导致的地热田未来地震灾害的可能性非常重要。活动。在这项拟议的工作中，选择了加利福尼亚州活跃构造环境下的三个可操作地热田，对应于三个遥远的大地震。本研究的重点是比较每个地热场 (~10x10 km^2) 及其分为几个分区的相邻断层带 (~100x100 km^2) 之间的不同行为。结果将解决以下问题：（1）地热场内部和外部的地震活动率如何响应每次远程地震？ (2) 地热田内外的应力场有何不同？ （3）浅源地震和深源地震如何响应远程触发？ （4）地热田内部净产量与地震活动率是否存在相关性？ (5) 地热田内外地震速度结构和原位Vp/Vs有何差异？