Collaborative Research: Acquisition of Continuous GPS and Borehole Geophysical Networks for Invertigations of Seismogenic Processes at the Costa Rica Subduction Zone

合作研究：获取连续 GPS 和钻孔地球物理网络以反演哥斯达黎加俯冲带的地震过程

• 批准号: 0502221
• 负责人: Timothy Dixon
• 金额: --
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0502221&HistoricalAwards=false
• 关键词: Collaborative; Research; Acquisition; Continuous; GPS

0502221DixonThis grant will support acquisition and installation of a 9 station network of continuously operating GPS stations (CGPS) and 3 boreholes broadband seismometers and tiltmeters on the Nicoya Peninsula to investigate slow slip events and episodic seismic tremor at the Costa Rican subduction zone. The new instrumentation will augment 3 existing CGPS stations deployed by Japanese and Costa Rican colleagues, and 6 borehole seismic observatories, being installed by German colleagues. These international collaborations will greatly enhance the ability of the network to address fundamental questions about earthquake processes in this hazardous region. Slow slip events or "silent earthquakes" are a recently observed mode of strain release where slip occurs over an intermediate time scale, usually days to months. This type of motion has been detected at a few subduction zone faults where continuous GPS or borehole tiltmeter networks exist. The processes responsible are poorly understood but slow slip events have been associated with low frequency seismic tremor, possibly caused by the migration of fluids through the shallow subduction system. Increased fluid pressure on the interplate fault could act to weaken it bringing it closer to failure. As a result, slow slip events may indicate pre-rupture fault breakdown prior to the occurrence of a large earthquake. The Nicoya Peninsula borehole seismic and CGPS networks will have sufficient density and sensitivity to detect and study slow slip events and seismic tremor and investigate the processes responsible for their generation.***

0502221 Dixon这笔赠款将用于支持在尼科亚半岛购置和安装9个连续运行的GPS台站（CGPS）和3个钻孔宽带地震仪和倾斜仪，以调查哥斯达黎加俯冲带的缓慢滑动事件和间歇性地震震颤。新仪器将增强日本和哥斯达黎加同事部署的3个现有CGPS台站，以及德国同事正在安装的6个钻孔地震观测站。 这些国际合作将大大提高该网络解决这一危险地区地震过程基本问题的能力。 缓慢滑动事件或“无声地震”是最近观察到的应变释放模式，其中滑动发生在中间时间尺度上，通常是几天到几个月。这种类型的运动已被检测到在几个俯冲带断层连续GPS或钻孔倾斜仪网络存在。人们对造成这种现象的过程知之甚少，但缓慢滑动事件与低频地震震颤有关，这可能是由流体通过浅层俯冲系统的迁移引起的。 板间断层上增加的流体压力可能会削弱它，使它更接近失败。因此，缓慢滑动事件可能表明大地震发生前的破裂前断层破裂。 尼科亚半岛钻孔地震和CGPS网络将具有足够的密度和灵敏度，以探测和研究缓慢滑动事件和地震震颤，并调查造成这些事件的过程。