Ice thickness estimates of Lemon Creek Glacier, Alaska, from active-source seismic imaging
Keyword
Glacier geophysicsglaciological instruments and methods
ice thickness measurements
mountain glaciers
seismology
Lemon Creek Glacier
temperate valley glacier
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Lemon Creek Glacier, a temperate valley glacier in the Juneau Icefield of Southeast Alaska, is the site of long running (>60 years) glaciological studies. However, the most recent published estimates of its thickness and subglacial topography come from two ∼50 years old sources that are not in agreement and do not account for the effects of years of negative mass balance. We collected a 1-km long active-source seismic line on the upper section of the glacier parallel and near to the centerline of the glacier, roughly straddling the equilibrium-line altitude. We used these data to perform joint reflection-refraction velocity modeling and reflection imaging of the glacier bed. We find that this upper section of Lemon Creek Glacier is as much as 150 m (∼65%) thicker than previously suggested with a large overdeepening in an area previously believed to have a uniform thickness. Our results lead us to reinterpret the impact of basal motion on ice flow and have a significant impact on expectations of subglacial hydrology. We suggest that further efforts to develop a whole-glacier model of subglacial topography are necessary to support studies that require accurate models of ice thickness and subglacial topography.Date
2021-03-26Publisher
Cambridge University PressType
ArticlePeer-Reviewed
YesCitation
Veitch SA, Karplus M, Kaip G, Gonzalez LF, Amundson JM, Bartholomaus TC (2021). Ice thickness estimates of Lemon Creek Glacier, Alaska, from active-source seismic imaging. Journal of Glaciology 67(265), 824–832. https://doi.org/10.1017/jog.2021.32Collections
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