An Experiment in Seismic Tomography: The Three-Dimensional Structure of the East Pacific Rise

地震层析成像实验：东太平洋海隆的三维结构

• 批准号: 8615797
• 负责人: G. Michael Purdy
• 金额: $ 44.9万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-04-15 至 1990-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8615797&HistoricalAwards=false
• 关键词: Experiment; Seismic; Tomography; Three; Dimensional

Understanding the processes that create new seafloor at mid- ocean ridges is a critical aspect of marine geological and geophysical research. Although it is now well accepted that seafloor spreading has created the present ocean crust during approximately the last 200 million years, the details by which new volcanic material is generated and emplaced at the ridges remains unresolved. An important unknown is the distribution and longevity of subsurface magma chambers in which partially melted mantle material is stored before being erupted to the seafloor. Recently acquired deep penetration seismic reflection data from the East Pacific Rise has revealed what appears to be the top of a fairly continuous magma chamber along the Rise crest. The objective of the present project is to use seismic refraction techniques to examine the magma chamber in more detail than can be obtained from the seismic reflection data. Specifically, the project will deploy a series of ocean bottom seismometer/hydrophones across the Rise crest and then use explosive and acoustic energy sources to record the horizontal transmission of energy through the crust. These data will be analyzed by recently developed tomographic techniques which allow three dimensional imaging using the entire data set. Specific questions to be addressed include the width, depth, and velocity structure of the subsurface magma chamber. This is a cooperative project between scientists at Woods Hole Oceanographic Institution and the Massachusetts Institute of Technology. The project will be funded at the following levels: Woods Hole -FY87=$30000, FY88=$297000, FY89=$87000 MIT -FY87=$30000, FY88=$163000, FY89=$133000

了解在中海脊中创建新海底的过程是海洋地质和地球物理研究的关键方面。 尽管现在已被公认为海底蔓延在过去的2亿年中造成了当前的海壳，但在山脊上生成和放置新的火山材料的细节仍未解决。 一个重要的未知是地下岩浆室的分布和寿命，其中在爆发到海底之前将部分融化的地幔材料储存。 最近从东太平洋崛起获得的深度渗透地震反射数据揭示了沿着山顶沿着相当连续的岩浆室的顶部。 本项目的目的是使用地震折射技术比从地震反射数据获得的更详细地检查岩浆腔。 具体而言，该项目将在上升波峰上部署一系列海洋底部地震仪/氢气，然后使用爆炸性和声学能源来记录能量通过地壳的水平传播。 这些数据将通过最近开发的层析成像技术分析，这些技术允许使用整个数据集进行三维成像。 要解决的具体问题包括地下岩浆室的宽度，深度和速度结构。 这是伍兹霍尔海洋学机构和马萨诸塞州理工学院的科学家之间的合作项目。 该项目将在以下级别上资助：伍兹孔-fy87 = $ 30000，fy88 = $ 297000，fy89 = $ 87000 MIT -FY87 = $ 30000，FY88 = $ 163000，FY89 = $ 133000 = $ 133000