Authorities issued a tsunami alert for the northeast coast Friday after a powerful 7.3-magnitude undersea earthquake struck, setting buildings in Tokyo swaying violently.
They said tsunami up to 1 meter high could sweep ashore in areas badly hit by the March 2011 tsunami that devastated a large swath of the Tohoku region coast, killing thousands.
A 1-meter wave was seen in the Ayukawa district in Ishinomaki, Miyagi Prefecture, shortly past 6 p.m., NHK said. In addition, a 20-cm wave was logged by a tsunami gauge off Kinkazan in Miyagi.
It wasn't immediately clear if the waves caused any damage.
Residents in cities along the Sanriku coast were advised to evacuate to higher ground.
Those include Rikuzentakata, Ofunato, Yamada in Iwate Prefecture, as well as Miyagino and Wabayashi wards in Sendai and Ishinomaki and Iwanuma in Miyagi Prefecture.
Telephone operator NTT said the network in the areas was jammed with the weight of calls.
A presenter on NHK repeatedly told viewers to get to safety.
"Remember last year's quake and tsunami," he said. "Call on your neighbors and flee to higher ground now!"
The U.S. Geological Survey put the quake's magnitude at 7.3. It said the temblor struck a relatively deep 36 km under the Pacific.
The epicenter was 284 km east of Sendai, or 459 km northeast of Tokyo, according to the USGS.
There was no threat of a Pacific-wide tsunami, U.S. monitors based in Hawaii said. Officials in both Indonesia and the Philippines said there was no threat of a localized tsunami.
Tokyo Electric Power Co. said there were no reports of any problems at its crippled Fukushima No. 1 nuclear plant.