Southern Japan hit by strong quake near Nankai Trough region

Southern Japan was hit by a strong earthquake on Monday that authorities said did not warrant the kind of megaquake warning that was triggered for the first time last year.

A quake with a preliminary magnitude of 6.9 struck the Kyushu region at 9:19 p.m. (0019 GMT) on Monday, the Japan Meteorological Agency said. After an investigation, the JMA said the quake did not warrant special measures related to seismic activity in the Nankai Trough.

The Nankai Trough, where the Philippine Sea Plate is slipping under the Eurasia Plate at the bottom of the sea off the southwest coast of Japan, produces massive earthquakes about every 100-150 years. Strong quakes nearby are seen as a potential indication that a megaquake could be more likely.

The JMA in August issued a week-long advisory for a “relatively higher chance” of a megaquake as powerful as magnitude 9 after a magnitude-7.1 quake hit the country’s southwest.

After Monday’s quake, tsunami advisories for waves of a maximum height of one metre (3.3 ft) were issued for the southern prefectures of Miyazaki and Kochi. A 20-centimetre (7.8 inches) tsunami was later recorded reaching Miyazaki city, public broadcaster NHK reported.

All tsunami advisories were lifted around 0250 GMT.

There were no abnormalities reported at the Ikata Nuclear Power Plant in western Japan or the Sendai Nuclear Power Plant in Kagoshima prefecture, NHK said, referring to the two plants nearest to where the quake occurred.

Earlier in November 2024, nearly 200,000 people in western Japan were urged to evacuate as authorities warned of landslides and floods, while the remnants of a tropical storm trickle over the country.

The Japan Meteorological Agency said “warm, moist air… was causing heavy rainfall with thunderstorms in western Japan” partly due to Kong-rey, which was downgraded to an extratropical low-pressure system from a typhoon.

The city of Matsuyama “issued the top-level warning, urging 189,552 residents in its 10 districts to evacuate and immediately secure safety”, a city official told AFP.

While the evacuation was not mandatory, Japan’s highest-level warning is typically issued when it is extremely likely that some kind of disaster has already occurred.

Forecasters warned that landslides and floods could affect western Japan on Saturday and eastern Japan on Sunday.

Due to rain, Shinkansen bullet trains were briefly suspended between Tokyo and southern Fukuoka region in the morning before resuming on a delayed schedule.

Kong-rey smashed into Taiwan on Thursday as one of the biggest storms to hit the island in decades.

It claimed at least three lives and injured 690 people, according to the National Fire Agency, which added a migrant worker death to the toll on Saturday.