September 4, 2018 Tsunami: Southern Japan

Reference #14273:

Typhoon Jebi was the most powerful typhoon to strike Japan in 25 years. It was formed as a tropical depression on 26 August 2018 and then rapidly intensified into a typhoon. This typhoon destructively affected the Northern Mariana Islands and then on 2 September caused huge waves and five fatalities on the coast of Taiwan. Propagating north-westward and then northward on 4 September, Jebi reached the south-eastern coast of Japan producing severe damage and intensive floods along the entire coasts of Shikoku Island and the Kansai region of Honshu Island. The typhoon existed for 15 days and ended on 9 September 2018.

The entire character of seiche generation by the propagating 2018 typhoon was comparable to that for the 2016 typhoon Lionrock. Similar to the 2016 event, the broad-band oscillations decay quickly after the 2018 typhoon’s passage, while narrow-band oscillations at resonant frequencies keep reverberating. In general, we may conclude that local topography (eigen properties of specific harbours and bays) plays a critical role in the generation of the extreme seiches, which can be considered as meteotsunamis. In this regard, these conclusions are in good agreement with those by Honda et al. (1908) and Nomitsu (1935), who were the first to show that the resonant properties of specific sites are central to the formation of tsunamis and tsunami-like waves on the coast of Japan.