Global S&T Development Trend Analysis Platform of Resources and Environment
项目编号 | 1538229 |
Love-wave propagation in oceanic upper mantle: constraints on radial anisotropy and implications for dynamics of the asthenosphere | |
James Gaherty | |
主持机构 | Columbia University |
项目开始年 | 2015 |
2015-09-01 | |
项目结束日期 | 2017-08-31 |
资助机构 | US-NSF |
项目类别 | Standard Grant |
项目经费 | 228554(USD) |
国家 | 美国 |
语种 | 英语 |
英文摘要 | The mechanisms that enable plate-like behavior on the Earth's surface and the processes that control plate motion are not fully understood. This study uses earthquake-generated seismic waves that were recorded by seafloor seismometers deployed for year in the central Pacific to probe the structure, particularly near the base of the plate. Using known relationships between deformation-induced mineral alignment and its effect on seismic signature, the degree of coupling between the plate and the underlying mantle will be evaluated. The question of how a rigid tectonic plate differs from the underlying mantle and whether or not these materials move in unison at the base of the plate, or not, has long intrigued Earth scientists. It is at the heart of understanding plate tectonics. The graduate student supported by this award will receive training in forefront marine seismic data analysis and have the opportunity to work with a unique dataset. Strong azimuthal seismic anisotropy in the Pacific lithosphere is consistent with observations of olivine alignment found in ophiolites, and it constrains models of ocean spreading center dynamics. In contrast, high-amplitude radial anisotropy observed in the Pacific asthenosphere provides evidence for a highly deformed and/or partially molten layer beneath the plate that may decouple the plate from the underlying mantle. A 600x400 km ocean bottom seismometer (OBS) array, located on ~70 Ma lithosphere, provided high-quality broadband seismic data, sufficient to characterize anisotropy with resolution (in depth and laterally) that is unattainable from global analyses. Rayleigh-wave velocities indicate extremely strong azimuthal anisotropy developed during formation of the lithosphere, but notably weaker azimuthal anisotropy is indicated in these data for the underlying asthenosphere. Determining the corresponding depth distribution of radial anisotropy requires detailed analysis of Love waves. Using a novel analysis of the wavefield, Love wave fundamental- and higher-mode phase velocities will be measured across the OBS array. Combined with the existing azimuthal anisotropy constraints, the resulting estimates of anisotropy will allow us to explicitly test whether flow-induced olivine fabric is consistent with the observations, or whether oriented melt is required to explain the observations. |
来源学科分类 | Geosciences - Ocean Sciences |
文献类型 | 项目 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/68652 |
专题 | 环境与发展全球科技态势 |
推荐引用方式 GB/T 7714 | James Gaherty.Love-wave propagation in oceanic upper mantle: constraints on radial anisotropy and implications for dynamics of the asthenosphere.2015. |
条目包含的文件 | 条目无相关文件。 |
个性服务 |
推荐该条目 |
保存到收藏夹 |
查看访问统计 |
导出为Endnote文件 |
谷歌学术 |
谷歌学术中相似的文章 |
[James Gaherty]的文章 |
百度学术 |
百度学术中相似的文章 |
[James Gaherty]的文章 |
必应学术 |
必应学术中相似的文章 |
[James Gaherty]的文章 |
相关权益政策 |
暂无数据 |
收藏/分享 |
除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。
修改评论