Low-Frequency Attenuation in Polycrystalline Silicates and Silicate Partial Melts

多晶硅酸盐和硅酸盐部分熔体的低频衰减

• 批准号: 0207642
• 负责人: Reid Cooper
• 金额: $ 23.19万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207642&HistoricalAwards=false
• 关键词: Low; Frequency; Attenuation; Polycrystalline; Silicates

Reid F. Cooper, Principal InvestigatorUniversity of Wisconsin-Madison The measurement of the low-frequency attenuation behavior of polycrystalline olivine aggregates, of olivine-orthopyroxene aggregates and of olivine-based partial melts will be pursued. Specifically, the polycrystalline materials, which will have carefully engineered microstructures, will be subjected to dynamic ("sub-resonant", oscillatory loading) and quasistatic (constant loading, i.e., creep) so as to evaluate the attenuation behavior as functions of (i) temperature (1150 to 1350 degC), (ii) frequency (2x10e-4 to 1 Hz), (iii) phase volume fraction and morphology (phase percolation and phase separation/layering in the solid state; melt segregation beyond the grain scale in partial melts), and (iv) dislocation-creep sub-microstructure. The study/characterization of microstructural effects (engineered into these specimens so as to mimic deformation-induced microstructures) on seismic-frequency absorption is one key to applying seismic data to infer deformation behavior in active tectonic terranes.

威斯康星大学麦迪逊分校首席研究员里德·F·库珀将继续测量多晶橄榄石集合体、橄榄石-斜方辉石集合体和橄榄石基部分熔体的低频衰减行为。具体地说，具有精心设计的微观结构的多晶材料将受到动态(亚共振，振荡加载)和准静态(恒定加载，即蠕变)的影响，以评估作为以下函数的衰减行为：(I)温度(1150℃至1350℃)，(Ii)频率(2x10e-4至1 Hz)，(Iii)相体积分数和形态(固态中的相渗透和相分离/分层；部分熔体中超出晶界尺度的熔体偏析)，以及(Iv)位错蠕变亚微观结构。研究/表征微结构对地震频率吸收的影响是应用地震数据推断活动构造地体变形行为的关键之一。