‘An earthquake with a magnitude of 6.9 was observed in the Hyuganada, off the coast of Miyazaki Prefecture, east of Kyushu, Japan. The Japan Meteorological Agency plans to investigate its relevance to the Nankai Trough megathrust earthquake.’
According to the Japan Meteorological Agency, at around 9:19 PM on the 13th, an earthquake with a magnitude of 6.9 was observed in the Hyuganada, off the coast of Miyazaki Prefecture, east of Kyushu, Japan. The depth of the epicenter is 30 km.
Immediately after the earthquake, the Japan Meteorological Agency issued a tsunami advisory for Miyazaki Prefecture and Kochi Prefecture in Shikoku. The expected maximum height of the tsunami in the regions under advisory is about 1 meter. The northern plains region of Miyazaki Prefecture experienced shaking of ‘intensity 5 lower.’
The Japan Meteorological Agency’s earthquake intensity scale, known as ‘intensity,’ is a relative concept that indicates the degree of shaking felt by people and objects, as opposed to magnitude, which measures absolute strength. ‘Intensity 5 lower’ is characterized by most people experiencing fear and items like dishes and books falling off shelves. Shaking of ‘intensity 4’ was detected in many other parts of Kyushu, including Fukuoka Prefecture, Saga Prefecture, and Kumamoto Prefecture.
According to NHK, the Japan Meteorological Agency has decided to investigate the connection between this earthquake and the Nankai Trough megathrust earthquake. Following a magnitude 7.1 earthquake off the coast of Miyazaki Prefecture in Kyushu on August 8 last year, an expert meeting concluded that the likelihood of a massive earthquake along the Pacific coast had increased beyond normal levels.
Based on this, the agency issued the ‘Nankai Trough Earthquake Temporary Information (Massive Earthquake Advisory)’ for the first time. The Nankai Trough megathrust earthquakes are believed to occur at intervals of 100 to 150 years along the Nankai Trough, which stretches from off the coast of Shizuoka Prefecture to the southern Shikoku and eastern Kyushu sea areas.
The Japanese government considers there is a 70-80% chance of the Nankai Trough megathrust earthquake occurring within 30 years. It is predicted that an earthquake with a magnitude of 8 to 9 could result in around 230,000 fatalities and missing individuals, and damage to 2.09 million buildings.