| 项目编号: | 1643761
|
| 项目名称: | Colloborative Research: Monitoring Antarctic Ice Sheet Changes with Ambient Seismic Noise Methods |
| 作者: | German Prieto
|
| 承担单位: | Massachusetts Institute of Technology
|
| 批准年: | 2017
|
| 开始日期: | 2017-05-01
|
| 结束日期: | 2019-04-30
|
| 资助金额: | 209116
|
| 资助来源: | US-NSF
|
| 项目类别: | Standard Grant
|
| 国家: | US
|
| 语种: | 英语
|
| 特色学科分类: | Geosciences - Polar
|
| 英文关键词: | ice sheet
; ice
; project
; ice-mass
; researcher
; change
; ice-sheet
; method
; seismic velocity change
; ice-sheet behavior
; ambient seismic noise field
; other modern ice-sheet monitoring technique
; passive seismic monitoring method
; ice-mass fluctuation
; seismological research
; variation
; passive seismology method
; repetitive seismic noise correlation function
; other method
; ice-rock interface
; new method
; poroelastic change
; ice-mass variation
; recent rapid ice loss
; crust
; surface-wave velocity change
; seismic method
; temporal change
; ice-mass change
|
| 英文摘要: | Non-technical description:
Global sea-level rise is a significant long-term risk to human population and infrastructure. To mitigate and properly react to this threat, society needs accurate predictions of future sea-level variations. The largest uncertainty in these predictions comes from estimating the amount of ice that melts from polar ice sheets, especially from the West Antarctica ice sheet. Right now, scientists estimate the mass variations of ice sheets in two ways. The first way is using airplanes and repeated flybys to monitor the variation of ice sheet topography and estimate the gain or loss of ice. The second way is using satellite measurements to track gravity fluctuations that correlate with the variation of ice sheet volume. Both techniques work, but both have limitations including cost and resolution. This project uses a passive seismic monitoring method to estimate the change in weight of the ice pressing on the Earth's crust. One advantage of this seismic method is that vibrations are recorded continuously; therefore, it is possible to monitor the changes of the ice sheet with better temporal resolution. The sensitivity of the seismic waves also provides a picture of the structure of the interface between the ice and the rocks beneath the ice, where most of the dynamics and changes of the ice sheet take place. This information is difficult to obtain with other methods. In this project, the researchers will process and analyze previously acquired seismic data from the POLENET-ANET array, measuring variations in seismic wave speed through time to assess the amount of ice lost or gained. They will also determine important information about the mechanical properties at the ice-rock interface. The project will support a postdoctoral scholar to develop this new branch of seismological research and more generally the field of environmental seismology. This project will also support the education of a PhD student who will work in close collaboration with the postdoctoral scholar and the two researchers.
Technical description:
The researchers plan to monitor ice-mass variations in the West-Antarctic ice sheet by measuring and interpreting seismic velocity changes in crust beneath the ice sheet. This project will extend similar work already completed on the Greenland ice sheet, where ice-mass fluctuations were found to lead to poroelastic changes in the crust and modify the seismic-wave velocity. This investigation uses a passive seismology method, whereby repetitive seismic noise correlation functions are computed from records of Earth's ambient seismic noise field. Measurements of the temporal changes in the correlation functions are made and then related to variations of the poroelastic properties of the crust. The physical model for the relationship between ice-mass change and surface-wave velocity change has previously been verified using GRACE satellite data in Greenland. This project will specifically focus on the recent rapid ice loss in Western Antarctica using data from the POLENET-ANET seismic network. A comparison between the ice-sheet behaviors in Greenland and Antarctica will provide clarification about the underlying physical processes responsible for the observed seismic velocity changes. This new method will be a transformative approach to monitor ice sheets with the potential for much higher spatial and temporal resolution than existing methods. The fact that this method relies on seismic waves makes the approach completely independent from other modern ice-sheet monitoring techniques. |
| 资源类型: | 项目
|
| 标识符: | http://119.78.100.158/handle/2HF3EXSE/90268
|
| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
|
|
There are no files associated with this item.
|
| Recommended Citation: | |
German Prieto. Colloborative Research: Monitoring Antarctic Ice Sheet Changes with Ambient Seismic Noise Methods. 2017-01-01.
|
|
|