Abstract
A large-scale volcanic eruption occurred in the Tongan Archipelago in the South Pacific Ocean on January 15th, 2022. Affected by this, changes in tidal levels were observed over a wide range of Japan’s the Pacific coast area from the night of January 15th to 16th. The highest tidal level reached 1.34 meters in Kominato, Amamishi City, Kagoshima Prefecture. The tidal changes are deemed to be caused by a mechanism that is different from the mechanism of earthquake-induced tsunami, but the Japan Meteorological Agency (JMA) used the framework of “tsunami warnings and advisories” from a disaster prevention perspective to urgently communicate the information to call on the residents to secure their safety. This is an interim report on how NHK and commercial broadcasters (Tokyo-based key stations) conveyed the JMA information on the unprecedented phenomenon different from tsunami.
