ミズホ カンソク キョテン デ カンソク シタ ヒョウシン

• Main Authors: 神沼, 克伊, カミヌマ, カツタダ, 高橋, 正義, タカハシ, マサヨシ, KAMINUMA, Katsutada, TAKAHASHI, Masayoshi
• Language: English
• Published: 国立極地研究所 1975
• Subjects: 550.34:551.2; Antarctic; Syowa Station; Mizuho; Antarc*; Antarctica
• Online Access: https://nipr.repo.nii.ac.jp/record/7835/files/KJ00002476938.pdf; https://doi.org/10.15094/00007835; https://nipr.repo.nii.ac.jp/records/7835

P(論文) 1973年9月,第14次越冬隊により,上下動1成分の地震計を用いた地震観測がみずほ観測拠点で行われた.観測条件の悪い南極の内陸基地での地震観測の試みは南極点基地以外には例が無いと思われる.基地内の人工的雑音などのため十分な観測ができなかったが合計210時間の間の記録をとることに成功し多くの氷震を観測した.その結果,この地域では気温が-35℃以下で,その変化の割合が1時間に-2.5℃以下,または-1℃/hourが数時間続く時には例外なく氷震が発生している. The wintering party of the 14th Japanese Antarctic Research Expedition carried out a temporary seismological observation with one vertical component seismograph at the Mizuho Camp on September 10-27, 1973. The Mizuho Camp is located at about 300km southeast of Syowa Station in Antarctica, where the ice thickness is about 2,100 m. The seismological observation was disturbed by the ground noise of many kinds of artificial origin, but good records for 210 hours in total were obtained. Natural earthquakes were not detected by this temporary observation, but many iceshocks, mostly of swarm type, were recorded. These swarms occurred in the nighttime. The air temperature during the iceshocks was below -35℃, and the falling rate of temperature was -2.5℃ per hour for a short period, or about -1℃/hour though the lowering continued for a few hours. When the largest swarm during this observation period occurred, the wintering members at the Mizuho Camp heard sound from shocks and recognized many cracks on the snow surface around the area of the sound. Therefore, the depth of the swarm was estimated to be very shallow. Some shocks were interpreted to have been originated from the upper snow layers quite near the surface, so they may be called snowquakes. departmental bulletin paper