Collaborative Research: Seismic, Aseismic and Slow Transient Deformation at the Costa Rica Seismogenic Zone

合作研究：哥斯达黎加地震带的地震、抗震和慢瞬变变形

• 批准号: 0506463
• 负责人: Susan Schwartz
• 金额: $ 16.54万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0506463&HistoricalAwards=false
• 关键词: Collaborative; Research; Seismic; Aseismic; Slow

A network of continuous GPS and six seismometers is being developed to monitor transient strain and seismic events above the subducting slab on the Nicoya Peninsula, northern Costa Rica. This will allow investigation of a number of seismogenic zone processes. One of the most exciting recent discoveries in the solid earth sciences is the occurrence of silent slip or aseismic creep events at subduction zones. The physical processes responsible for these events are not well understood; detection and study of their behavior at several locations is important. Aseismic creep episodes have been observed prior to the occurrence of large earthquakes and therefore may have important implications for earthquake hazard. Creep episodes perturb the surrounding stress field and their occurrence at the down dip edge of the seismogenic zone could bring the megathrust closer to failure. These stress increases are small, however if the fault is close to failure aseismic creep could trigger a large earthquake.Relative to other subduction zones, Nicoya has a big advantage for this type of project: the peninsula is quite close to the trench. Instruments deployed here are essentially perched directly over the locked part of the plate boundary, enabling high-resolution study of plate boundary strain and seismic processes. The correlation between deep episodic creep and low frequency tremor, recently uncovered at the Cascadia subduction zone, could be significant in deciphering the key physical processes. The project is an international collaboration with scientists from Costa Rica. Germany, Japan and the United States.

正在开发一个由连续全球定位系统和六个地震仪组成的网络，以监测哥斯达黎加北方尼科亚半岛俯冲板块上方的瞬时应变和地震事件。 这将允许调查一些孕震区的过程。 在固体地球科学中最令人兴奋的新发现之一是在俯冲带中发生的无声滑动或无声蠕变事件。造成这些事件的物理过程还没有得到很好的理解;在几个地点检测和研究它们的行为很重要。在大地震发生之前已经观察到了无震蠕变事件，因此可能对地震灾害具有重要意义。蠕变事件扰动周围的应力场，它们发生在孕震区的下倾边缘，可能会使大型逆冲断层更接近失败。这些应力的增加很小，但是如果断层接近破坏，地震蠕变可能会引发大地震。相对于其他俯冲带，尼科亚进行这类项目有一大优势：半岛离海沟相当近。 部署在这里的仪器基本上直接位于板块边界的锁定部分，从而能够对板块边界应变和地震过程进行高分辨率研究。 最近在卡斯卡迪亚俯冲带发现的深层幕式蠕动和低频震颤之间的相关性对于破译关键物理过程可能具有重要意义。该项目是与来自哥斯达黎加的科学家进行的国际合作。德国、日本和美国。