1983-1984 ネン マクマードサウンド チイキ ノ コクサイ キョウドウ カンソク

1983-1984年のマクマードサウンド地域の国際共同観測は, 第4年目を迎えた「エレバス火山国際地震研究(IMESS)」を実施した。日本からは神沼克伊(国立極地研究所), 植木貞人(東北大学理学部), 小山悦郎(東京大学地震研究所)の3名が参加した。日本隊はテレメータ観測網の記録系の保守, 観測した磁気テープの再生, 読み取りを担当している。今回は, 日本隊が2点のテレメータ新観測点の設置をしたほか, エレバス山山腹に8点, ドライバレーのバンダ基地に1点の地震計を設置し, 約45日間臨時観測を行った。エレバス山頂からの熱放射を調べるため, 噴煙活動を約10時間ビデオテープレコーダに記録した。またロス島, エレバス山腹, 山頂付近など合計21点で重力測定を実施した。Three Japanese scientists visited McMurdo Station from November 11,1983 to January 16,1984 to participate in the International Mt. Erebus Seismological Studies (IMESS). This was the fourth year of the cooperation project among Japan, the United States and New Zealand. The members for this season are K. KAMINUMA (National Institute of Polar Research), S. UEKI (Faculty of Science, Tohoku University) and E. KOYAMA (Earthquake Research Institute, the University of Tokyo). The following research programs were carried out : 1. Seismic observation by the telemetry network : Japanese scientists played back the magnetic tapes which have been recorded since October 1983. The daily frequencies of volcanic earthquakes occurring in and around Mt. Erebus were counted and earthquakes were scaled. The Japanese members together with the American group established two new stations. 2. Observations by a temporary seismic network : From November 18,1983 to January 3,1984,eight seismic stations were established on the flank of Mt. Erebus for precise determination of the earthquake locations. One station was also establish at Vanda Station, in the Wright Valley for detecting local earthquakes from December 19,1983 to January 17,1984. 3. Gravity measurements : LaCoste-Romberg gravimeter model G was used at eight temporary seismic stations and five telemetry seismic stations. Four additional gravity stations were established on the northeast side of the summit crater of Mt. Erebus and other four stations at outcrops in the eastern part of Ross Island