Strong earthquake in northeastern Japan

The magnitude 6.4 earthquake struck yesterday in northern Japan, causing sea levels to change slightly, but authorities did not issue a tsunami warning.

>>>The strange effects of Japanese earthquakes

The epicenter of the 6.4-magnitude Richter earthquake is off the coast of Iwate Prefecture (red symbol). (Graphic: USGS)

AP quoted the Japan Meteorological Agency as saying that the epicenter was located off the coast of Iwate, northeastern Japan, at a depth of 10km under the sea. There are slight changes in sea level but do not cause tsunami warnings.

The earthquake occurred 8pm (local time), 500km away from Tokyo, about 80km from the nearest city Morioka, the capital of Iwate province. A Morioka resident told CNN that he felt a strong shaking within 40 seconds but was not strong enough to drop books on the ground.

Iwate was heavily damaged in the March earthquake and tsunami. The 9-magnitude earthquake caused tsunamis on March 11, 2011, killing 19,000 and missing, damaging a series of cities along the northeastern coast of Japan. The double disaster a year ago also caused the worst nuclear incident in history since the Chernobyl nuclear disaster.

No damage and casualties were reported after yesterday's earthquake. Nor were there any abnormalities reported from regional nuclear power plants, including the crippled Fukushima I plant after the 2011 tsunami.

Last week, Japan announced it had temporarily suspended most nuclear power plants across the country to check safety. There is only one out of 54 nuclear reactors operating in Japan.