THE volcano Kusatu-Sirane suddenly became active with a remarkable explosion on November 27, 1937, and from that time until October 1938 it was studied in great detail by T. Minakami (Bull. Earthquake Res. Inst.,Tokyo Imp. Univ., 17, Part 3, September 1939, pp. 590-623). The volcano was very active during December 1937, and January and February 1938. It was more calm from April.until August 1938, but became active again from the latter part of September. A rather violent explosion occurred on October 5, 1938, and after that date large quantities of gas were ejected, while ash was scattered near the ?crater. At the same time, volcanic pulsations and volcanic micro-earthquakes occurred and these were still continuing in February 1939.