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

目前正在开发一个由连续GPS和6个地震仪组成的网络，以监测哥斯达黎加北部尼科亚半岛俯冲板块上方的瞬态应变和地震事件。这将使我们能够研究一些发震带过程。固体地球科学最近最令人兴奋的发现之一是在俯冲带发生了无声滑动或地震蠕变事件。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是很重要的。在大地震发生之前已经观察到地震蠕变事件，因此可能对地震危险性具有重要意义。蠕变事件扰乱了周边应力场，它们在孕震带的下倾边缘的出现可能使巨型逆冲断层更接近破裂。这些应力增加很小，但如果断层接近破裂，地震蠕变可能引发大地震。相对于其他俯冲带，尼科亚在这类项目中有很大的优势：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，可以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部偶发性蠕变和低频震颤之间的相关性，可能对破译关键的物理过程具有重要意义。该项目是哥斯达黎加科学家的国际合作项目。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.