Japan hit by strong earthquake near Nankai Trough region

Southern Japan was hit by a powerful earthquake today that authorities said did not warrant the kind of mega-quake warning first issued last year.

An earthquake with a preliminary magnitude of 6.9 struck the Kyushu region at 9:19 p.m. (02:19 Hawaii time) today, the Japan Meteorological Agency said. After an investigation, the JMA said the earthquake did not warrant special measures related to seismic activity in the Nankai Trough.

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

The JMA issued a week-long warning in August of a “relatively higher chance” of a magnitude 9 mega-quake after a magnitude 7.1 earthquake struck the country’s southwest.

Following today’s earthquake, tsunami warnings for waves with a maximum height of 3.3 ft were issued for the southern prefectures of Miyazaki and Kochi. A 7.8-inch tsunami was later recorded reaching Miyazaki city, public broadcaster NHK reported. “Based on all available data, a destructive tsunami is not expected in the Pacific Ocean and there is no tsunami threat to Hawaii,” the Pacific Tsunami Warning Center said in a bulletin.

All tsunami warnings 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 closest to where the quake struck.