Variations and Controls on the Up- and Down-Dip Limits of the Central America Seismogenic Zone

EAR-0229876 Susan Y.Schwartza在哥斯达黎加北部和中部几乎确定了地震孕育区的一级特征，包括其几何形状和上下倾角界限。这是通过在孕震区正上方部署两个陆上/近海地震台网来实现的，这两个台网是边缘资助的多学科孕震区实验(CRSEIZE)的一部分。这项建议的目的是：1)利用实验期间收集的数据，结合当地网络数据，建立尼加拉瓜地震孕育区的类似一级特征；2)详细调查哥斯达黎加北部和尼加拉瓜从板间地震活动向板内地震活动转变过程中的变化；3)评估为控制这一转变而提出的热和力学模型。这些GOLAS将通过同时反演哥斯达黎加北部和尼加拉瓜的当地旅行时数据来完成，以获得高分辨率的三维P和S波速度结构和准确的震中位置。地震位置加上震源机制的确定将使人们能够确定尼加拉瓜南部活跃的地震发生带，哥斯达黎加北部(尼科亚)台网的增加极大地改善了台站覆盖范围和震中精度。

EAR-0229876Susan Y. SchwartzA first-order characterization of the seismogenic zone, including its geometry and up and down-dip limits is nearly established in northern and central Costa Rica. This was accomplished through the deployment of two onshore/offshore seismic networks directly above the seismogenic zone that were part of a MARGIN's funded multidisciplinary seismogenic zone experiment (CRSEIZE). This proposal seeks to: 1) use data collected during this experiment in conjunction with local network data to establish a similar first-order characterization of the seismogenic zone in Nicaragua; 2) perform a detailed investigation of the variations in the transition from inter to intra plate seismicity in northern Costa Rica and Nicaragua; and 3) evaluate thermal and mechanical models that have been proposed to control this transition. These golas will be accomplished by simultaneously inverting local travel time data in northern Costa Rica and Nicaragua to obtain an high resolution, three-dimensional, P and S wave velocity structure and accurate hypocentral locations. Earthquake locations coupled with focal mechanism determinations will allow the active seimogenic zone to be identified in southern Nicaragua, where the addition of stations from the northern Costa Rica (Nicoya) network greatly improves station coverage and hypocentral accuracy.