Activities of Japanese earth science research in the McMurdo Sound region in the 1983-1984 season

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