| 项目编号: | 1358510
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| 项目名称: | Analysis of Seismic Data from the USArray Project to Determine Crust and Uppermost Mantle Structure Beneath the United States |
| 作者: | Peter Shearer
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| 承担单位: | University of California-San Diego Scripps Inst of Oceanography
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| 批准年: | 2013
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| 开始日期: | 2014-07-01
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| 结束日期: | 2016-06-30
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| 资助金额: | USD179944
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Earth Sciences
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| 英文关键词: | project
; united states
; structure
; crust
; crustal thickness
; analysis
; eastern united states
; uppermost mantle
; uppermost mantle depths
; usarray project
; uppermost mantle structure
; uppermost mantle variation
; uppermost mantle p
; seismic wave
; seismic velocity
; project study earthquake
; recent usarray station deployment
; crustal velocity
; crustal vp/vs ratio
; recent usarray datum
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| 英文摘要: | During the last ten years, NSF's USArray Project has deployed thousands of seismometers across the United States to record both local and distant earthquakes. Analyses of these data have provided greatly improved images of the structure of Earth's crust and mantle beneath the United States. This project studies earthquakes and quarry blasts recorded by USArray at distances up to 1600 km away (1000 miles), which are particularly useful for probing crustal thickness and the structure of the uppermost mantle, i.e., immediately below the crust at depths of about 35 to 50 kilometers (about 20 to 30 miles). Maps showing variations in the measured velocities of seismic waves in this region provide clues regarding the history and evolution of mountains, faults, and other geological features, including the Colorado Plateau and Yellowstone volcanism. This project builds on previously NSF funded work in the western United States to focus on more recent USArray data from the eastern United States.
In particular, the project uses regional seismic phases such as Pn, Sn, Pg and Lg, to produce new maps of crustal thickness and both isotropic and anisotropic variations in uppermost mantle P and S velocity that can be related to many surface tectonic features. These results generally agree with previous studies in their large-scale patterns but show more detail in many regions. Owing to its relatively sparse station coverage and lack of earthquakes, the eastern United States has been much less studied than the west, so the most recent USArray station deployments provide a valuable opportunity to probe its crust and uppermost mantle structure. This project will provide new crustal thickness maps, estimates of crustal Vp/Vs ratios, maps of uppermost mantle variations in seismic velocity and azimuthal anisotropy. In addition, analyses of Sn propagation efficiency and Pg and Lg times and amplitudes are planned to resolve lower crustal velocities and attenuation. These results will complement shear-wave splitting and surface- and body-wave tomography studies by providing superior resolution for structures at lower crustal and uppermost mantle depths. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/96380
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Peter Shearer. Analysis of Seismic Data from the USArray Project to Determine Crust and Uppermost Mantle Structure Beneath the United States. 2013-01-01.
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