Two-Ship Multichannel Seismic Investigation of the East Pacific Rise South of the Garret Fracture Zone

这是一个双船多道地震现场项目， 将提供第一个详细的地球物理限制， 地壳结构沿着东太平洋隆起以南的 加勒特断裂带。将收集三种类型的数据： (1)二十道密距单船地震 沿着东太平洋海隆的反射剖面; 五个双船展开剖面沿着并平行于 在同一地区的上升轴;（3）700公里长 沿着东太平洋多通道地震反射剖面 从加勒特断裂带上升到大重叠 扩展中心在20.5S。这些数据将用于测试 岩浆房大小的扩展速率依赖性， 许多山脊顶部的热模型，检查关系， 地壳岩浆房和沿轴向的变化之间的关系， 形态学、分段和玄武岩地球化学， 更好地解决海洋一级地震结构 地壳，包括莫霍面和地震层3，在 地壳形成后的几十万年。的 加勒特断裂带以南的东太平洋隆起部分 该区域将是全球地理信息网络倡议的一个主要重点。

This is a two-ship multichannel seismic field program that will provide the first detailed geophysical constraints on the crustal structure along the East Pacific Rise south of the Garrett fracture zone. Three types of data will be collected: (1) twenty closely-space, single-ship multichannel seismic reflection profiles along the East Pacific Rise; (2) twenty- five two-ship expanding spread profiles along and parallel to the rise axis in this same area; and (3) a 700-km-long multichanel seismic reflection profile along the East Pacific Rise from the Garrett fracture zone to the large overlapping spreading center at 20.5S. These data will be used to test the spreading rate dependence of magma chamber size predicted by many ridge crest thermal models, examine the relationship between crustal magma chambers and along-axis changes in morphology, segmentation and basalt geochemistry, and to resolve better how the first-order seismic structure of oceanic crust, including Moho and seismic layer 3, developed during the first few hundred thousand years after crustal formation. The section of the East Pacific Rise south of the Garrett fracture zone is to be a major focus of the RIDGE initiative.