Continuous seismic observations have been carried out since December 1980 by a cooperative International Mount Erebus Seismological Studies (IMESS) which includes Japan, the United States and New Zealand. Three Japanese participating in the IMESS visited McMurdo Station during the 1984-1985 field season. They were K. KAMINUMA and K. SHIBUYA (National Institute of Polar Research), and K. NIIDA (Faculty of Science, Hokkaido University). They conducted a series of scientific research programs during their tenure at McMurdo Station from 11 November 1984 to 15 January 1985. 1. Seismic observation by the telemetry network : Japanese scientists played back the magnetic tapes which have recorded since September 1984. The daily frequencies of eruptions and volcanic earthquakes occurring in and around Mount Erebus were counted and earthquakes were scaled. 2. Explosion seismic experiments : From 3 to 26 December 1984 seven seismic stations were established on the summit and the flank of Mount Erebus for the explosion seismic experiments and for precise determination of earthquake locations. 3. Gravity : Five new gravity stations were established on Ross Island during the 1984-1985 field season. 4. Geological survey : In order to enhance the study of the structure of the McMurdo volcanoes using both geophysical and geological methods, geological surveys were also carried out. Field studies were made on the volcanic rocks and the xenoliths of Cape Bird, Cape Crozier, Hut Point Peninsula and Black Island.