MARGINS: Seismic Evidence for Hydration of the Central American Slab: Guatemala Through Costa Rica

智力上的优点。流体进出俯冲带的循环在火山弧的形成中起着不可或缺的作用。中美洲俯冲带是研究流体对弧形和下伏地幔楔形和俯冲板块影响的理想地点，因为其输入和输出各不相同。现有的地球化学研究表明，沿这一弧线的板片水化程度差异很大，板片对岩浆生成的最大和最小贡献分别位于尼加拉瓜和哥斯达黎加下方。地球化学研究表明，在萨尔瓦多和危地马拉的地下也存在板岩流体的贡献，但在西北部有所减弱。地球物理研究与尼加拉瓜下方高度蛇纹化和流体释放一致，而科斯塔下方相对较少，但在其他方面，弧形的其余部分地球物理特征较差--主要是因为萨尔瓦多和危地马拉下方的板块没有很好地分辨。本研究将利用所有现有的地震数据，将为哥斯达黎加和尼加拉瓜开发的速度模型扩展到弧形的西北段，从而能够对地震结构和流体分布之间的关系进行区域分析。向国际地震中心报告的数据将与危地马拉通过哥斯达黎加的地方地震台网提供的更多数据结合在一起，该台网从未被整合起来研究整个中美洲俯冲区。这项研究将通过使用双差速度层析成像和重新定位方法，获得中美洲俯冲带内板片和地幔楔体的更广泛的地震图像。拟议的项目将主要支持一名年轻女科学家(锡拉丘兹)的专业发展，她以前没有得到过国家科学基金会的资助。锡拉丘兹大学将参与威斯康星大学麦迪逊分校的研究、教学和学习一体化计划。达美航空支持现有和未来的科学、技术、工程和数学教师提高学生的学习水平。

Intellectual merits. The cycling of fluids into and out of subduction zones plays an integral role in the formation of volcanic arcs. The Central American subduction zone is an ideal location for studying the effects of fluid on the arc and underlying mantle wedge and subducted slab due to its varying inputs and outputs. Existing geochemical studies indicate wide variability in degree of slab hydration along this arc, with maximum and minimum slab contributions to magma generation localized beneath Nicaragua and Costa Rica, respectively. Geochemical studies suggest that slab fluid contributions are also present beneath El Salvador and Guatemala, but diminish to the northwest. Geophysical studies are consistent with a high degree of slab serpentinization and fluid release beneath Nicaragua, versus comparatively little beneath Costa, but otherwise the rest of the arc is poorly characterized geophysically - primarily because the slab is not well-resolved beneath El Salvador and Guatemala. The present study will utilize all available seismic data to extend the velocity model developed for Costa Rica and Nicaragua into the northwestern section of the arc, allowing regional analysis of the relation between seismic structure and fluid distribution. Data reported to the International Seismic Centre will be combined with additional data from local seismic networks from Guatemala through Costa Rica, which has never been integrated to study the entire Central American subduction zone. This study will obtain a more extensive seismic image of the slab and mantle wedge within the Central American subduction zone through the use of a double difference velocity tomography and relocation method.Broader Impacts. The proposed project will primarily support the professional development of a young female scientist (Syracuse), who has not has prior NSF support. Syracuse will participate in the UW-Madison DELTA program for Integrating Research, Teaching, and Learning. DELTA supports current and future faculty in science, technology, engineering and math in their improvement of student learning.