Effects of Upper Mantle Phase Transitions on Seismic Motions

上地幔相变对地震运动的影响

• 批准号: 9526905
• 负责人: John Wahr
• 金额: $ 11.28万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-15 至 1999-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9526905&HistoricalAwards=false
• 关键词: Effects; Upper; Mantle; Phase; Transitions

9526905 Wahr This research is to study the possible effects of upper mantle phase transformations, for example at depths of 410 and 660 km, on seismic motions, especially the free oscillations of the earth. Preliminary estimates suggest that during seismic motions, material in the vicinity of a phase boundary could change phase as it oscillates. For example, perturbations to the eigenfrequencies of free oscillations due to the 660 km boundary could be anywhere from a few tenths to several percent, well within the observational uncertainties of the eigenfrequencies. The objectives are to study whether the inversion of free oscillation data for spherical structure could provide useful information on the 410 and 660 km discontinuities; and to judge whether the inclusion of phase transformation effects into the inversion process might improve the inversions for other parameters. For the latter, the work will focus especially, though not exclusively, on implications for the density profile in the transition zone, and on the bulk dissipation models that have been inferred from observations of radial mode attenuation. *** ??

9526905 WAHR这项研究是为了研究上地幔相变的可能影响，例如410和660 km的深度对地震运动，尤其是地球的自由振荡。 初步估计表明，在地震运动中，相边界附近的材料在振荡时可能会改变相。 例如，由于660 km边界而引起的自由振荡特征频率的扰动可能是从几个百分之十到百分之几，远离了本征频率的观察性不确定性。 这些目标是研究球形结构的自由振荡数据是否可以提供有关410和660 km不连续性的有用信息；并判断将相变效应纳入反转过程是否可以改善其他参数的反转。 对于后者而言，尤其不是仅仅（尽管并非完全集中）对过渡区的密度曲线的影响，以及从径向模式衰减观察到的散装耗散模型上。 *** ??