TOKYO, Dec. 9 (Xinhua) -- Japan's weather agency lifted a tsunami warning for coastal areas of Aomori, Iwate and Hokkaido prefectures early on Tuesday, hours after an earthquake with a preliminary magnitude of 7.5 struck northeastern Japan.
The powerful temblor occurred at 11:15 p.m. local time on Monday off Aomori's Pacific coast at a depth of 54 km, measuring upper 6 on Japan's seismic scale of 7 in parts of Aomori, said the Japan Meteorological Agency (JMA).
About three and a half hours after the quake struck, the tsunami warning was downgraded to an advisory. At 6:20 a.m. local time on Tuesday, all tsunami advisories for the Pacific coastal areas were lifted.
The JMA, which revised the magnitude of the quake down from 7.6, warned of tsunami of up to 3 meters following the quake. The highest tsunami observed was about 70 centimeters at Kuji Port in Iwate.
Japanese Prime Minister Sanae Takaichi said Tuesday that 30 people were injured in the powerful earthquake, warning of a similar or even stronger temblor in Pacific coastal areas.
The weather agency has issued an alert for a potential mega quake following Monday's quake, noting there is a one-in-100 chance that an 8-magnitude quake or greater could occur within seven days.
The Cabinet Office called on the public to maintain special readiness for at least a week, such as by keeping an emergency supply kit within reach, so they can evacuate at a moment's notice if necessary.
The Chinese Embassy in Japan issued a notice early on Tuesday, urging Chinese citizens in the country to stay vigilant and closely monitor earthquake updates, weather warnings and disaster prevention information.
In Aomori and Hokkaido, there have been reports of more than 10 injuries, including at least one serious case in Hokkaido's Hidaka, with no fatalities so far. The Aomori prefectural government said that around 2,700 homes experienced power outage, Kyodo News reported.
No abnormalities have been reported by nuclear plants in Hokkaido or the northeastern prefectures of Aomori, Miyagi and Fukushima, the report said.
Tohoku Shinkansen bullet train services have been halted between Fukushima and Shin-Aomori stations, operator JR East said. A bullet train carrying 94 passengers was briefly stranded in Aomori. ■
