TOKYO - An 8.3 magnitude earthquake struck off Japan's northern coast in the Pacific on Saturday, setting off tsunami warnings and sending thousands of residents along the archipelago's eastern coast fleeing to higher ground.
A tsunami warning also was issued for Alaska's western Aleutian islands and a tsunami watch was issued for Hawaii.
Japan's Meteorological Agency had said that waves as high as 3.3-feet could hit the northeastern coast of Japan's main island of Hokkaido around 2 p.m. (12 a.m. ET), and that waves half that size could hit western Japan around 4 p.m.
But about an hour later, a tidal swell of about 4 inches was recorded in the northeastern coastal town of Nemuro, the agency said.
Officials had said earlier that the tide receded about 4 inches in Nemuro, in the first signs that a tsunami was approaching. Most other areas said there had been no visible changes to the sea level.
Small swells in the tide were also observed in other coastal towns on the island, including Kushiro, Abashiri and Otaru, the agency said.
The quake struck around 1:24 p.m. about 310 miles east of Etorofu, the largest of a disputed four-island chain known as the Northern Territories in Japan and the Kuril islands in Russia, the agency said.
The quake struck 19 miles below the seabed, the agency said.
The U.S. Geological Survey registered the earthquake with a magnitude of 8.2.
There were no immediate reports of injuries or damage from the quake, Hokkaido state police spokesman Shinji Yamakoshi said.
Meanwhile, residents of two remote Aleutian Islands evacuated Friday night after officials issued a tsunami warning for Alaska's western Aleutian islands. A less serious tsunami watch was issued for Hawaii.
Temblors of magnitude 7 are generally classified as major earthquakes, capable of widespread, heavy damage.
The Japanese meteorological agency also issued warnings last November following a magnitude 7.9 quake in a similar area, but most areas saw waves of only about 7.8 inches.
Seismologists, however, warned that this time the quake was stronger and cautioned residents to remain vigilant.
Tokyo University seismologist Yoshinobu Tsuji warned that high waves may still hit the region, hours after a tsunami warning. "I urge everyone to stay alert," he said.
On Dec. 26, 2004, a magnitude-9.0 earthquake off Indonesia's Sumatra island spawned giant waves that fanned out across the Indian Ocean at jetliner speeds, leaving at least 230,000 dead and millions of homeless in its wake.
