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Glaciological and marine geological controls on terminus dynamics of Hubbard Glacier, southeast Alaska
Author(s) -
Stearns L. A.,
Hamilton G. S.,
van der Veen C. J.,
Finnegan D. C.,
O'Neel S.,
Scheick J. B.,
Lawson D. E.
Publication year - 2015
Publication title -
journal of geophysical research: earth surface
Language(s) - English
Resource type - Journals
eISSN - 2169-9011
pISSN - 2169-9003
DOI - 10.1002/2014jf003341
Subject(s) - fjord , tidewater glacier cycle , glacier , tidewater , geology , glacier terminus , shoal , tributary , oceanography , iceberg , geomorphology , physical geography , ice calving , ice stream , ice sheet , geography , cryosphere , sea ice , pregnancy , cartography , lactation , biology , genetics
Hubbard Glacier, located in southeast Alaska, is the world's largest nonpolar tidewater glacier. It has been steadily advancing since it was first mapped in 1895; occasionally, the advance creates an ice or sediment dam that blocks a tributary fjord (Russell Fiord). The sustained advance raises the probability of long‐term closure in the near future, which will strongly impact the ecosystem of Russell Fiord and the nearby community of Yakutat. Here, we examine a 43 year record of flow speeds and terminus position to understand the large‐scale dynamics of Hubbard Glacier. Our long‐term record shows that the rate of terminus advance has increased slightly since 1895, with the exception of a slowed advance between approximately 1972 and 1984. The short‐lived closure events in 1986 and 2002 were not initiated by perturbations in ice velocity or environmental forcings but were likely due to fluctuations in sedimentation patterns at the terminus. This study points to the significance of a coupled system where short‐term velocity fluctuations and morainal shoal development control tidewater glacier terminus position.