气候变化领域集成服务门户(CCPortal): Grounding zone subglacial properties from calibrated active-source seismic methods

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DOI	10.5194/tc-15-1863-2021
	Grounding zone subglacial properties from calibrated active-source seismic methods
	Horgan H.J.; Van Haastrecht L.; Alley R.B.; Anandakrishnan S.; Beem L.H.; Christianson K.; Muto A.; Siegfried M.R.
发表日期	2021
ISSN	19940416
起始页码	1863
结束页码	1880
卷号	15 期号:4
英文摘要	The grounding zone of Whillans Ice Stream, West Antarctica, exhibits an abrupt transition in basal properties from the grounded ice to the ocean cavity over distances of less than 0.5-1 km. Active-source seismic methods reveal the downglacier-most grounded portion of the ice stream is underlain by a relatively stiff substrate (relatively high shear wave velocities of 1100 ±430 m s-1) compared to the deformable till found elsewhere beneath the ice stream. Changes in basal reflectivity in our study area cannot be explained by the stage of the tide. Several kilometres upstream of the grounding zone, layers of subglacial water are detected, as are regions that appear to be water layers but are less than the thickness resolvable by our technique. The presence of stiff subglacial sediment and thin water layers upstream of the grounding zone supports previous studies that have proposed the dewatering of sediment within the grounding zone and the trapping of subglacial water upstream of the ocean cavity. The setting enables calibration of our methodology using returns from the floating ice shelf. This allows a comparison of different techniques used to estimate the sizes of the seismic sources, a constraint essential for the accurate recovery of subglacial properties. We find a strong correlation (coefficient of determination = 0.46) between our calibrated method and a commonly used multiple-bounce method, but our results also highlight the incomplete knowledge of other factors affecting the amplitude of seismic sources and reflections in the cryosphere. © Author(s) 2021.
英文关键词	calibration; grounding line; seismic method; subglacial environment
语种	英语
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202333
作者单位	Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand; Department of Geosciences, Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, United States; Department of Earth Sciences, Montana State University, Bozeman, MT 59717, United States; Earth and Space Sciences, University of Washington, Seattle, WA 98195, United States; Department of Earth and Environmental Science, Temple University, Philadelphia, PA 19122, United States; Department of Geophysics, Colorado School of Mines, Golden, CO 80401, United States
推荐引用方式 GB/T 7714	Horgan H.J.,Van Haastrecht L.,Alley R.B.,et al. Grounding zone subglacial properties from calibrated active-source seismic methods[J],2021,15(4).
APA	Horgan H.J..,Van Haastrecht L..,Alley R.B..,Anandakrishnan S..,Beem L.H..,...&Siegfried M.R..(2021).Grounding zone subglacial properties from calibrated active-source seismic methods.Cryosphere,15(4).
MLA	Horgan H.J.,et al."Grounding zone subglacial properties from calibrated active-source seismic methods".Cryosphere 15.4(2021).