Japan issued a tsunami (search) warning Wednesday after a 6.8-magnitude earthquake struck off its eastern coast, but officials later said the waves generated posed little danger.
The quake struck at 3:11 p.m. about 120 miles off the coast of Chiba state, the Meteorological Agency said. It was centered six miles below the ocean floor. The shaking was weak and hardly felt in Tokyo (search) or nearby areas.
The agency issued warnings for tsunami, or waves caused by seismic activity, as high as 20 inches near the Izu Island chain on the Pacific Ocean, but later announced they posed little danger of damage. Japan's (search) meteorological agency issues tsunami warnings even when expected wave size is relatively small as a precaution.
Waves ranging in height from about 4-12 inches were recorded at the Izu islands, the agency announced about an hour after the quake.
Officials on nearby islands took precautions.
Yoshinori Takahashi, a chief of disaster prevention on the island of Izu Oshima, said there were no reports of tsunami hitting the island's shores.
"We have not seen any changes on the water around the island," Takahashi said about 20 minutes after the tsunami was expected to hit the island. "We have issued a tsunami warning on our public speaker system set up throughout the island to warn residents not to approach the coast."
On Kozu Island, town spokesman Akiyoshi Shimizu, said officials have gone down to ports to check any changes. So far, no major damages have been reported, he added.
Stuart Weinstein, a geophysicist at the Pacific Tsunami Warning Center in Honolulu, said the quake failed to generate a Pacific-wide tsunami, saying U.S. experts measured the quake at a magnitude of 6.4, below the threshold for the center issuing any kind of advisory.
The Dec. 26 tsunami that killed more than 160,000 in South Asia and Africa was generated by a 9.0 earthquake near Indonesia under the Indian Ocean. The region does not have a tsunami alert system. Wednesday's quake occurred under the Pacific Ocean near Japan, a region that possesses such a system.