TOKYO — A series of earthquakes rattled Tokyo and northeastern Japan on Wednesday evening but caused no apparent damage or injury in the same region hit by last year's devastating tsunami.
The strongest was a magnitude 6.8 that struck off Hokkaido island and generated a small tsunami. Some communities along the northern Pacific coast advised residents to evacuate coastal homes.
A swelling of 20 centimeters (8 inches) was observed in water at the port of Hachinohe in Aomori about an hour after the tremor, with smaller changes seen elsewhere. The Meteorological Agency lifted all tsunami advisories within about 90 minutes.
About 9 p.m. local time, a magnitude-6.1 quake shook buildings in the capital. It was centered just off the coast of Chiba, east of Tokyo, at a rather shallow 15 kilometers (9 miles) deep.
Narita International Airport briefly closed runways for inspection but later resumed operation. Several local train services were suspended for safety checks.
There were no abnormalities reported at nuclear power plants after the two earthquakes, operators said. Nearly all of Japan's nuclear plants are offline for safety inspections.
This past Sunday, Japan marked the first anniversary of the massive magnitude-9.0 earthquake and tsunami that left some 19,000 people dead or missing, wreaked widespread damage along the northeastern coast and triggered the worst nuclear accident since Chernobyl. Rebuilding has yet to fully begin in many coastal communities.
Wednesday's temblors were considered aftershocks of last year's massive quake, Meteorological Agency official Akira Nagai told a news conference, warning residents to stay away from buildings already damaged by it and the thousands of aftershocks since.
The town of Otsuchi in Iwate prefecture, where more than 800 died in last year's tsunami, told residents to evacuate coastal households as a precaution after Wednesday's quake, said prefectural disaster management official Shinichi Motoyama. No damage or injury was reported, he said.
Nearly all of the thousands of aftershocks from last year's earthquake have been of minor or moderate strength.
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By MARI YAMAGUCHI 03/14/12 12:32 PM ET