Magnetotelluric investigation of fluid- and melt-involved processes in the Central American subduction zone

这里提出的建议旨在扩大最近在“MT中美洲”项目初期阶段在中美洲边际进行的工作。在哥斯达黎加西北部和尼加拉瓜西北部进行了两个区域尺度、长周期的边缘大地电磁剖面，根据其他地球物理和地球化学参数的沿走向变化，获得了明显的俯冲带流体和熔体的电磁图像。扩展当前项目的需要是基于：i)沿两条横断面的地电参数清楚地表达了必须建模的三维特征。ii)必须完成IFM-Geomar进行的海上测量与陆上数据集的整合。此外，斯克里普斯海洋学研究所将在尼加拉瓜海沟进行一个近海样带，并将在陆地上设立新的监测站加以补充和完成。最终目标是获得边缘的完整三维图像，将电参数与地震学和地球化学发现联系起来，并加强对沿走向趋势的理解，特别是尼加拉瓜-哥斯达黎加边界火山弧的突然偏转。

The proposal presented here aims at extending the work which has recently been carried out at the Central American margin during the initial phase of project “MT Central America”. Two regional-scale, long-period magnetotelluric profiles at the margin were conducted in north-western Costa Rica and northwestern Nicaragua, which yielded distinct electromagnetic images of fluids and melts of the subduction zone, in accordance with along-strike variation of other geophysical and geochemical parameters.The need to extend the current project is based on: i) The geoelectric parameters along both transects clearly express three-dimensional characteristics which have to be modeled. ii) The integration of offshore measurements conducted by IFM-Geomar into the onshore data set has to be completed. iii) Furthermore, Scripps Oceanographic Institution will carry out an offshore transect across the Nicaraguan trench, which shall be supplemented and completed with new stations on land. The final goal is to achieve a full three-dimensional image of the margin, to correlate the electric parameters with seismological and geochemical findings and enhance understanding of the along-strike trends, particularly the sudden deflection of the volcanic arc at the Nicaraguan - Costa Rican border.