Southern Japan hit by 6.6-magnitude quake near Nankai Trough, tsunami warnings lifted

A strong earthquake recently struck southern Japan, but authorities say it did not reach the level of a super-earthquake alert, which was first triggered last year. The Japan Meteorological Agency stated that the initial magnitude of the earthquake in the Kyushu region was 6.9, occurring at 9:19 PM local time on Monday.

Subsequently, the earthquake's magnitude was revised to 6.6. After investigation, the Japan Meteorological Agency stated that no special measures related to the Nankai Trough earthquake activity were required. The Nankai Trough, located off the southwest coast of Japan, is where the Philippine Sea Plate subducts beneath the Eurasian Plate, and a large-scale earthquake occurs roughly every 100-150 years.

Japan frequently experiences earthquakes due to its location in the Ring of Fire, an arc of volcanoes and fault lines in the Pacific Basin. Meteorological Agency experts held a meeting on Monday evening to assess the correlation between the latest earthquake and the Nankai Trough earthquake, but decided not to take any special measures for the time being. In 1946, a Nankai Trough earthquake near Shikoku resulted in the loss of over 1,300 lives.

Last August, the region experienced a 7.1 magnitude earthquake. Strong earthquakes in the vicinity are considered potential signs that a super-earthquake might be more likely to occur. Last August, following the 7.1 magnitude earthquake in the southwest, the Japan Meteorological Agency issued a week-long alert indicating a "relatively high probability of a super-earthquake occurring," potentially reaching a magnitude of 9.

Following Monday's earthquake, tsunami advisories of up to one meter were issued for southern Miyazaki and Kochi prefectures. Public broadcaster NHK reported that a 20-centimeter tsunami was subsequently recorded in Miyazaki City. All tsunami advisories were lifted around noon. NHK also stated that no abnormalities were reported at the Ikata nuclear power plant, the closest to the epicenter, or at the Sendai nuclear power plant in Kagoshima Prefecture.