| 项目编号: | 1624077
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| 项目名称: | Constructing a model from the spreading centers to backarc: Resolving geophysical characteristics of segmentation in Cascadia |
| 作者: | Haiying Gao
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| 承担单位: | University of Massachusetts Amherst
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| 批准年: | 2016
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| 开始日期: | 2016-09-01
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| 结束日期: | 2019-08-31
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| 资助金额: | 288469
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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: | segmentation
; along-strike
; along-strike variation
; subduction
; subduction-related segmentation
; high-resolution three-dimensional velocity model
; cascadia subduction zone
; spreading center
; intriguing characteristic
; cascadia initiative amphibious array
; entire cascadia subduction zone
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| 英文摘要: | Subduction plays a major role in driving plate tectonics on Earth and controls many fundamental tectonic processes. Subduction zones are the source of many great earthquakes, volcanic eruptions, tsunamis, and landslides, all of which have significant impacts on natural systems and society. One intriguing characteristic of subduction zones worldwide is the presence of along-strike variation (segmentation) in a wide variety of properties and processes. Understanding along-strike variation is key to our understanding of many subduction/arc processes, such as magmatism and earthquake hazards. The Cascadia subduction zone in the Pacific Northwest exhibits along-strike variation in many aspects, spanning from the spreading center to the backarc. A superb data set is available with the deployments of the EarthScope Transportable Array, the Cascadia Initiative Amphibious Array, and many flexible arrays. This project aims to provide constraints on the relationships between structure of the incoming plate and the along-strike variation of the subducted slab, mantle wedge, and lithospheric base by generating a high-resolution three-dimensional velocity model for the entire Cascadia subduction zone. High-resolution characterization of the crust structure is also critical to refine seismic hazard assessment in the Pacific Northwest.
Seismic tomography provides a powerful way to delineate the three dimensionality of subduction-related processe and to constrain the relations among the various modes of segmentation. Recent seismic studies image discrete low-velocity volumes along the forearc at shallow depths, beneath the oceanic Moho around the trench, and beneath the back-arc within the mantle, indicating structural correlations from offshore to onshore. I will implement a joint 3D full-wave simulation and inversion of ambient noise and regional earthquake arrivals, which will provide the highest possible resolution for the Juan de Fuca and Gorda plates prior to and after subduction. Specifically, this proposal will address the following scientific questions: (1) What are the geometry and properties of the Juan de Fuca and Gorda plates prior to and after subduction? What is the role of the incoming oceanic plate(s) on the segmentation? (2) What structural correlations can be imaged from the spreading centers to the backarc that may give insight to the segmentation? What are the resolvable dimensions of the segmented features from the crust to the upper mantle? Understanding of subduction-related segmentation obtained in this study will provide a key perspective that can be applied to other subduction zones, which has broad importance to Earth and Planetary Sciences. One female early-career geoscientist, who is in the process of establishing a new seismology group at UMASS-Amherst, will be supported for the career development. The proposed work will support training of undergraduate and graduate students. The related products will be integrated into ongoing public outreach and introductory classes in Earth Science. Wave propagation simulation and ground motion maps are great tools to educate the public in New England about seismic hazards. The outcome will be introduced to 8th-12th grade girls through the Girls Inc. Eureka! Program, a strong STEM-based collaboration between Girls Inc. of Holyoke, Massachusetts and UMASS. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/91162
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Haiying Gao. Constructing a model from the spreading centers to backarc: Resolving geophysical characteristics of segmentation in Cascadia. 2016-01-01.
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