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: 9106233
• 负责人: Douglas Toomey
• 金额: $ 2.88万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-03-15 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9106233&HistoricalAwards=false
• 关键词: Experiment; Seismic; Tomography; Three; Dimensional

In January 1988 a seismic tomography experiment was carried out on the East Pacific Rise at 9 degrees 30'N to image in three dimensions the seismic velocity structure of the rise axis. This experiment yielded a seismic data set consisting of more that 8000 records from approximately 500 shots and 15 ocean bottom seismometers. Initial result from the tomographic inversion of P wave delay times indicate substantial heterogeneity in structure both across and along the rise axis; for instance, the axial low velocity anomaly at 2 km depth is 1.5km/s slower than off axis; the along-axis variations in this velocity anomaly exceed 20% This renewal will continue the investigation of seismic velocity models using improved inversion techniques, will explore methods of utilizing wave form amplitude information to constrain further the 3-D seismic structure, and will analyze and interpret the gravity, magnetic, and microearthquake data obtained during thecourse of the tomograph experiment.

1988年1月，在东太平洋隆起北纬9度30度处进行了地震层析成像实验，对隆起轴的地震速度结构进行了三维成像。这个实验产生了一个地震数据集，由大约500次射击和15个海底地震仪的8000多条记录组成。P波延迟时间层析反演的初步结果表明，沿上升轴和沿上升轴的结构均存在明显的非均匀性；例如，2 km深度轴向低速异常比离轴慢1.5km/s；本次更新将继续利用改进的反演技术研究地震速度模型，探索利用波形振幅信息进一步约束三维地震结构的方法，并分析和解释重、磁、以及层析成像实验过程中获得的微震数据。