17. On the Tsunami Generated by the Miyakejima-Kinkai Earthquake on December 28, 1982

1982年12月28日三宅島近海に発生した群発地震で,八丈島八重根検潮所において全振幅40cmの小津波が観測された.しかし,それ以外の伊豆諸島の検潮記録では風浪による顕著な副振動と重なり,津波は検知できなかった.A small tsunami was generated by the Miyakejima-Kinkai earthquake (M=6.8) near Mikura Island, Izu Islands, 200km south of Tokyo. At Yaene, Hachijo Island, the initial disturbance of the present tsunami was observed with an upward motion of 20cm with a wave period of 8min and the maximum double amplitude was 40cm. On the records at other tidal stations, the tsunami is not evident because of the swell with amplitude of 20-30cm. Tsunami magnitude (Imamura-Iida scale) may be m=0.5