Cascadia Basin basement tectonics, temporal and spatial development of the sediment cover, and evolution of the hydrothermal flow system

2004年夏季，IODP第1段将在Juan de Fuca Ridge的东侧进行钻探。该研究的主要课题是研究玄武质海洋地壳的区隔性、各向异性、微生物学和物理性质，以阐明一个活跃的脊侧热液系统的性质，该热液系统很大程度上孤立于低渗透沉积物覆盖之下。在so149号R/V Sonne巡航期间进行的高分辨率地震现场前调查，对IODP第1阶段的计划做出了重大贡献。在Second Ridge的主要地点附近，有一个紧密间隔（100米）的二维地震线网格。First Ridge的次要站点是基于高分辨率3D网格进行规划的。到目前为止，这两个地震数据集都是使用标准处理方案作为现场调查的一部分进行处理的。现在，人们建议通过更详细的速度模型、仔细的反褶积和替代（3D）迁移技术来进一步改善叠加和迁移结果。在再处理的基础上，将仔细绘制褶皱、断层和层状结构。该假设将被验证，即强迫折叠是影响沉积物物理性质和流体流动的主要过程。

In summer 2004, IODP Leg 1 will be drilled on the eastern flank of the Juan de Fuca Ridge. The main subject of the leg is to study compartmentalization, anisotrophy, microbiology and physical properties of basaltic oceanic crust in order to elucidate the properties of an active ridge flank hydrothermal system, which is for a big part isolated benath a low permeable sediment cover. The high resolution seismic pre-site survey, which was carried out during R/V Sonne Cruise SO 149, substantially contributed to get IODP Leg 1 scheduled. In the vicinity of the primary sites at Second Ridge, a grid of closely spaced (100 m) 2D seismic lines are available. Secondary sites on First Ridge were planned based on a high resolution 3D grid. So far, both seismic data sets were processed as part of the site survey using a standard processing scheme. It is now proposed to further improve the stacking and migration results with respect to more detailed velocity models, careful deconvolution, and alternative (3D) migration techniques. Based on the reprocessing, folds, faults, and the layer structure will be carefully mapped. The hypothesis will be tested that forced folding is a dominant process affecting sediment physical properties and fluid flow...