SGER - Hydrologic Monitoring of Leaking Coseismically Active Thrusts: A Pilot Study in the Nankai Subduction Zone

SGER - 同震活跃逆冲泄漏的水文监测：南开俯冲带的试点研究

• 批准号: 0628676
• 负责人: Kevin Brown
• 金额: $ 5.21万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0628676&HistoricalAwards=false
• 关键词: SGER; Hydrologic; Monitoring; Leaking; Coseismically

AbstractUnder this award, the PIs will undertake a pilot study of the interaction of tectonics and hydrogeology at the Nankai accretionary wedge of Japan. The study entails the deployment of five instruments for one year monitoring of cold seeps along the major coseismically active out-of-sequence thrust (OOST) zones. The PIs have been invited on a 3-week Japanese cruise that will investigate the seeps and deploy the instruments. These thrusts link directly down to the seismogenic zone, are known to leak fluids, and numerous seeps have been identified along them. Recent observations indicate that this OOST region is also the location from which very low frequency (VLF) earthquakes appear to be originating that may be tied to ultra slow earthquakes near the updip limit of the seismogenic zone. The PIs will be using instrumentation that has been shown to be capable of collecting long-term records of fluid flow, temperature, and both aqueous and gas chemistry in active seep environments. By comparing these flow records to nearby borehole seismic records (and perhaps Japanese OBS records), The PIs hope to clarify the relationship between subsurface fluid pressure pulses and stress release eventsrelated to the VLF events.The broader impacts of this study come primarily through its direct relevance to major international programs of research and natural hazard mitigation. The field area is the focus of a significant portion of IODPs NantroSeize drilling program. It is also intended to help initiate a highly collaborative partnership between US, and Japanese scientists. Eventually, the instrumentation we will be using can be networked as part of a long-term monitoring system. Studying fault instabilities in an earthquake and tsunami generating subduction zone has direct human and political impact.

摘要 根据该奖项，PI 将在日本南海增生楔上开展构造学和水文地质学相互作用的试点研究。 该研究需要部署五台仪器，对沿主要同震活跃无序逆冲（OOST）区域的冷渗进行一年监测。 PI 已受邀参加为期 3 周的日本巡航，将调查渗漏情况并部署仪器。这些逆冲断层直接连接到地震带，已知会泄漏液体，并且沿它们已发现许多渗漏点。最近的观测表明，该 OOST 地区也是极低频 (VLF) 地震的发源地，这可能与发震带上倾极限附近的超慢地震有关。 PI 将使用已被证明能够收集活跃渗透环境中的流体流量、温度以及水和气体化学的长期记录的仪器。通过将这些流动记录与附近的井眼地震记录（或许还有日本 OBS 记录）进行比较，PI 希望澄清地下流体压力脉冲和与 VLF 事件相关的应力释放事件之间的关系。这项研究的更广泛影响主要来自于其直接影响与重大国际研究计划和减轻自然灾害的相关性。现场区域是 IODP NantroSeize 钻井计划的重要部分的重点。它还旨在帮助美国和日本科学家之间建立高度合作的伙伴关系。最终，我们将使用的仪器可以联网，作为长期监测系统的一部分。研究地震和海啸产生的俯冲带中的断层不稳定性具有直接的人类和政治影响。