The Japan Meteorological Agency’s study group said in a draft report compiled 15 March that the tidal surges differed from those generated by a strong offshore earthquake.
It noted that disturbances in the atmosphere were detected after the eruption of the Hunga Tonga-Hunga Ha’apai volcano around 1 pm. on 15 January.
The resulting air pressure waves reached near the Honshu main island, about 8,000 kilometers from the volcano, around 8:40 p.m., according to an analysis of images captured by Japan’s Himawari weather satellite.
