TOKYO, Dec. 8 (Xinhua) -- An earthquake with a preliminary magnitude of 7.6 struck northeastern Japan late Monday night, with tsunami waves of 40 centimeters having been recorded in areas along the Pacific coast, the country's weather agency said.

The temblor occurred at 11:15 p.m. local time at a depth of 50 km, measuring upper 6 on Japan's seismic scale of 7 in the hardest-hit areas, said the Japan Meteorological Agency (JMA).

The agency has issued a tsunami warning for the coastal areas of Hokkaido, Aomori, and Iwate prefectures, with waves up to 3 meters expected.

Tsunami waves of 40 cm have been observed off Aomori and Hokkaido prefectures, the JMA said.

No abnormalities were detected at Fukushima, Higashidori, and Onagawa nuclear plants, public broadcaster NHK reported.

A tsunami advisory has also been issued for Miyagi and Fukushima prefectures following the powerful quake, according to the JMA. ■