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

正在开发一个由全球定位系统和六台地震仪组成的连续网络，以监测哥斯达黎加北部尼科亚半岛俯冲板块上方的瞬时应变和地震事件。这将允许对一些孕震带过程进行调查。固体地球科学中最令人兴奋的最新发现之一是在俯冲带发生无声滑动或无地震蠕动事件。造成这些事件的物理过程还不是很清楚；对它们在几个地点的行为进行检测和研究很重要。在大地震发生之前已经观察到了无地震蠕变幕，因此可能对地震危险性有重要的意义。蠕变幕扰乱了周围的应力场，它们出现在孕震带下倾边缘，可能会使巨型逆冲更接近破裂。这些应力增加很小，然而，如果断层接近破裂，地震蠕变可能会引发大地震。相对于其他俯冲带，尼科亚对于这种类型的项目有很大的优势：半岛离海沟很近。部署在这里的仪器基本上直接位于板块边界的锁定部分，从而能够高分辨率地研究板块边界应变和地震过程。最近在卡斯卡迪亚俯冲带发现的深幕蠕变与低频地震之间的相关性，可能对破译关键的物理过程具有重要意义。该项目是与哥斯达黎加科学家的国际合作。德国、日本和美国。

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.