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

2004年夏天，IODP第1标段将在胡安德富卡山脊东侧进行钻探。该项目的主要内容是研究玄武岩洋壳的分区化、各向异性、微生物学和物理性质，以阐明活动的脊侧热液系统的性质，该系统在很大程度上是一个孤立的海底低渗透沉积物盖层。在R/V Sonne Cruise SO149期间进行的高分辨率地震现场前勘测，对IODP第1航段的预定做出了重大贡献。在第二山脊的主要场地附近，有一个密集分布的(100米)2D地震线的网格。First Ridge上的次要地点是基于高分辨率3D网格规划的。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。现在建议在更详细的速度模型、仔细的反褶积和替代(3D)偏移技术方面进一步改进叠加和偏移结果。在重新加工的基础上，将仔细绘制褶皱、断层和地层结构图。这一假设将得到检验，即强迫褶皱是影响沉积物物性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...