Constrained Optimal Solutions in Seismic Imaging

地震成像中的约束最优解

• 批准号: 8707889
• 负责人: Freeman Gilbert
• 金额: $ 15.26万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 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: 1987-09-01 至 1990-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8707889&HistoricalAwards=false
• 关键词: Constrained; Optimal; Solutions; Seismic; Imaging

The scope of our continuing research is the application of image reconstruction or tomographic techniques to a systematic and rigorous study of the Earth's laterally-heterogenous mantle and core seismic velocity structures. In the course of the initial funding period of this proposal, using a large-matrix, row-action inversion method that was developed, tested and refined during the first stages of our analysis, we have constructed spherically-symmetric, lower-mentle P and S-wave velocity models as well as P and S-wave seismic-station travel- time residual correction sets. We are using travel-time data from the International Seismological Centre's (ISC) short- period, global earthquake catalog. Nearly 2.4 million source- receiver data points from 24,423 earthquakes, representing teleseismic P and S ray paths in the 25o-105o epicentral distance range (bottoming depths from 700 kilometers to the core-mantle boundary) were used in the model inversions. The P results and the S velocity model show significant variation and improvement from results obtained by other studies and the S station correction set is possibly the first usable set ever developed. Using these improved models of both the lower mantle's spherically averaged structure and the upper-mantle and crustal lateral velocity variations as starting models, we are continuing and extending our analysis in a systematic investigation of the structure of the Earth's mantle, outer and inner core and core-mantle boundary.

我们持续研究的范围是应用图像重建或断层扫描技术对地球横向非均质地幔和核心地震速度结构进行系统而严格的研究。 在本提案的初始资助期间，我们使用在分析的第一阶段开发、测试和完善的大矩阵行作用反演方法，构建了球对称、低中心P和S波速度模型以及P和S波地震台走时残差校正集。 我们使用国际地震中心 (ISC) 短期全球地震目录中的走时数据。 模型反演中使用了来自 24,423 次地震的近 240 万个源接收器数据点，代表了 25o-105o 震中距离范围（底部深度从 700 公里到核幔边界）的远震 P 和 S 射线路径。 P 结果和 S 速度模型显示出与其他研究获得的结果相比的显着变化和改进，并且 S 站校正集可能是有史以来开发的第一个可用的校正集。 使用这些改进的下地幔球形平均结构以及上地幔和地壳横向速度变化模型作为起始模型，我们正在继续和扩展我们的分析，对地幔、外核和内核以及核-地幔边界的结构进行系统研究。