On the contraction of borehole at Mizuho Station, East Antarctica

元データ 国立極地研究所


Changes of borehole diameters at different depths down to 400m were estimated. Results are as follows : 1) Applying the flow law which was deduced from borehole closure observations by PATERSON (Rev. Geophys. Space Phys., 15,47,1977), the tertiary creep will start after about half of a year and the diameter of the hole will be 2/3 of the initial in a year and 1/10 after 2 years at a depth of 400m, provided that the shifting from the secondary to the tertiary occurs at total strain, ε=0.1. But the rate is 3 to 4 times larger when the flow law derived by MAE (J. Glaciol., 24,53,1979) from the flow observations at Mizuho Plateau is used. 2) The borehole closure rate has much difference depending on the flow law of ice. In order to induce a representative flow law of ice in Mizuho Plateau, the importance of borehole observation and technical development of boring is emphasized.


Tanaka Yoichi Geosystems Inc.
Takahashi Akiyoshi Geo Tecs Co. Ltd.
Takahashi A Geo Tecs Co. Ltd. Nagoya
Hasemi Tatsuo Institute of Geo-Technology
Takahashi Akiyoshi Institute of Geo-Technology
Ikegami Koichi Institute of Geo-Technology
Tanaka Yoichi Institute of Geo-Technology
Tanaka Yoichi Research Institute Of Atmospherics Nagoya University