| 项目编号: | 1543187
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| 项目名称: | Collaborative Research: Characterizing Brittle Failure and Fracture Propagation in Fast Ice Sliding with Dynamic Rupture Models based on Whillans Ice Stream Seismic/Geodetic Data |
| 作者: | Susan Schwartz
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| 承担单位: | University of California-Santa Cruz
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| 批准年: | 2016
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| 开始日期: | 2016-04-01
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| 结束日期: | 2018-03-31
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| 资助金额: | 39886
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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 - Polar
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| 英文关键词: | ice stream
; ice sheet
; ice
; ice motion
; ice shelf
; ice flow
; ice discharge
; rupture process
; mechanical model
; stick-slip cycle
; elastodynamic material response
; 3d waveform modeling
; brittle fracture process
; modeling tectonic earthquake
; ice fracture
; stick-slip
; predictive modeling
; 3d dynamic rupture model
|
| 英文摘要: | This project investigates a rapidly moving section of the West Antarctic Ice Sheet known as the Whillans Ice Stream. Ice streams and outlet glaciers are the major pathways for ice discharge from ice sheets into the ocean. Consequently, understanding ice stream dynamics, specifically the processes controlling the frictional resistance of ice sliding on sediments at its base, is essential for predictive modeling of how Earth's ice sheets will respond to a changing climate. Rather than flowing smoothly, Whillans Ice Stream advances in stick-slip cycles: brief periods of rapid sliding, equivalent to magnitude 7 earthquakes, alternating with much longer periods of repose. The PIs will perform simulations of these stick-slip cycles using computer codes originally developed for modeling tectonic earthquakes. By matching observed ice motions, the PIs will constrain the range of frictional processes acting at the base of the ice stream. An additional focus of the project is on brittle fracture processes in ice, expressed through seismic waves radiated by faulting and/or crevassing episodes that accompany the large-scale sliding events. An understanding of ice fracture provides a basis for assessing the susceptibility of ice shelves to rifting and catastrophic disintegration. Project results will be incorporated into outreach activities (from elementary school to community college events) as well as a polar science class for the California State Summer School for Mathematics and Science (COSMOS) program for high school students.
Simulations of the stick-slip cycle will employ 3D dynamic rupture models that simultaneously solve for the seismic wavefield and rupture process, consistent with elastodynamic material response and friction laws on the ice stream bed. Stresses and frictional properties will be varied to achieve consistency with surface GPS and broadband seismic data as well as borehole seismograms from the WISSARD project. The results will be interpreted using laboratory till friction experiments, which link velocity-weakening/strengthening behavior to temperature and water content, and to related experiments quantifying basal drag from ice flow over rough beds. The source mechanism of seismicity accompanying the slip events (shear faulting versus crevassing) will be determined using 3D waveform modeling in conjunction with mechanical models of the seismic source processes. This proposal does not require fieldwork in the Antarctic. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/92576
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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: | |
Susan Schwartz. Collaborative Research: Characterizing Brittle Failure and Fracture Propagation in Fast Ice Sliding with Dynamic Rupture Models based on Whillans Ice Stream Seismic/Geodetic Data. 2016-01-01.
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