A tsunami up to 30 m (98 feet) could hit Hokkaido in northern Japan and Iwate in the northeast if an M9 quake occurs off the Pacific coast, a government panel warned Tuesday, April 21, 2020, based on a worst-case scenario, adding that a mega-earthquake centered around the Japan Trench and the Kuril Trench could be 'imminent.'
The professional panel under the Cabinet Office showed the estimates, which came after assessing seismic intensity distributions and tsunami heights, in the event a tremor happens in an area, including the northern part of the Japan Trench and the Kuril Trench. The area is situated near the focus zone of the March 2011 earthquake and tsunami. The event ravaged northeastern Japan and killed 15 000 people.
The Cabinet Office panel said it is difficult to calculate the probability such an earthquake could occur, but it pointed to the fact that massive tsunamis have happened in the region every 300 to 400 years with the latest observed in the 17th century.
"A massive earthquake of this class (shown in the simulation) would be difficult to deal with by developing hard infrastructure (such as coast levees). To save people's lives, the basic policy would be an evacuation," Seismologist Keji Satake, the head of the panel and a professor at the University of Tokyo, stated.
The previous simulation by the panel based on the study of tsunami deposits in the past 6 000 years covered damage to seven prefectures, which are Hokkaido, Aomori, Iwate, Miyagi, Fukushima, Ibaraki, and Chiba.
The largest tsunami, up to 29.7 m (97.4 feet) is predicted to hit Miyako in the prefecture of Iwate, then Erimo in Hokkaido.
Areas around Tokyo Electric Power Company Holdings Inc.'s Fukushima Daiichi nuclear power plant, which was paralyzed by the 2011 calamity, is forecast to be hit as well, while a tsunami around 5 to 20 m (16 to 66 feet) could slam the coast of Miyagi and Fukushima
Parts of Aomori facing the Sea of Japan may also be affected, as well as Mutsu Bay, with the prefectural government office and Aomori city hall predicted to be submerged under more than 1 m (3 feet) of water.
The Cabinet Office launched a group to calculate the predicted disaster's impacts on people, buildings, and the economy, as well as the possible countermeasures. The conclusions will be released by the end of March 2021.