open access

https://hdl.handle.net/2115/50877

Characteristics of a crater glacier at Ushkovsky volcano, Kamchatka, Russia, as revealed by the physical properties of ice cores and borehole thermometry

英語

2001-07

International Glaciological Society

Journal of Glaciology

47(158)

423-432

A glacier at the summit of Ushkovskyvolcano, Kamchatka peninsula, Russia, was studied in order to obtain information about the physical characteristics of a glacier that fills a volcanic crater. The glacier has a gentle surface and a concave basal profile with a maximum measured depth of 240 m at site K2. The annual accumulation rate was 0.54 m a-1 w.e., and the 10 m depth temperature was -15.8°C. A 211.70 m long ice core drilled at K2 indicates that (1) the site is categorized as a percolation zone, (2) the stress field in the glacier changes at 180 m depth from vertical and longitudinal compression with transversal extension, which is divergent flow, to a shear-dominated stress field, and (3) the frequent occurrence of ash layers can be a good tool for dating the ice core. The borehole temperature profiles were considered to be non-stationary, but the linear profile made it possible to estimate the basal temperature and the geothermal heat flux at K2. Assuming constant surface and the basal boundary-conditions, we constructed two depth-age relationships at K2. These predicted that the bottom ages of the ice core were about 511 or 603 years.

学術雑誌論文

Version of Record

© 2001 International Glaciological Society

0022-1430

1727-5652

AA0025244X