komori_2004.htm
Bulletin of Glaciological Research 21 (2004)
49-56
©Japanese Society of Snow and Ice
Variation and lake expansion of Chubda Glacier, Bhutan Himalayas, during the last 35 years
Jiro KOMORI1, Deo Raj Gurung1, 2, Shuji IWATA1 and Hironori YABUKI3
1 Department of Geography, Tokyo Metropolitan University, Tokyo, 192-0397 Japan
2 Geological Survey of Bhutan, P.O. Box 173, Thimphu, Bhutan,
3 Frontier Observational Research System for Global Change, Kanagawa 236-0001 Japan
Abstract
Chubda Tsho (Chubda Glacial Lake), located in the headwater of Chamkhar River, is one of the largest glacial lakes in the Bhutan Himalayas. To assess the Glacial Lake Outburst Flood (GLOF), map and satellite image analyses, and field investigations were carried out. The results showed the past and present features of the glacier and the glacial lake. The horizontal location of the front of Chubda Glacier has not changed, at least during the last 35 years, and the present surface elevation of the debris-covered part of the glacier has obviously dropped. The area of Chubda Tsho expanded by about threefold through the years from 1967 to 2001. This expansion rate is slightly slower than those of other glacial lakes in the Eastern Himalayas. Assuming that the pace of expansion was constant, the initial water area would have appeared in the late 1950s to the early 1960s. The features of the lower end of the glacier are gravitationally stable under current conditions. However, the existence of collapse scars and the remaining ice core in the terminus suggest the potential danger of failure. In addition, the situation of the rocks and glacial ice on the upper part of the lake, which can be a trigger of GLOF, has not been understood. Therefore, detailed investigations of both the lower part of the glacial lake and the upstream of the glacier are required.
