An earthquake with a preliminary magnitude of 7.3 hit northern Japan on Tuesday, the Japan Meteorological Agency said, generating a tsunami that hit the nation's northern Pacific coast.
The U.S. Geological Survey initially put Tuesday's quake at a magnitude of 7.3 but down graded it to 6.9.
The earthquake, which was felt in Tokyo, was centered off the coast of Fukushima prefecture at a depth of about 10 km (6 miles) and struck at 5:59 a.m. (2059 GMT) the agency said.
USGS said that it was a shallow quake, at about 10 kilometers, which tended to cause more shaking damage and had greater potential to cause a tsunami.
"The good news here is that the direction the fault was moving is a slight lateral slip. When the faults move laterally they do not create the vertical movement associated with large tsunamis," the U.S. agency said.
A 60 cm (2 foot) tsunami had been observed at Fukushima's Onahama Port and a 90 cm (3 foot) tsunami at Soma soon after, public broadcaster NHK said. The region is the same that was devastated by a tsunami following a massive earthquake in 2011. A tsunami warning of up to 3 meters (10 feet) has been issued.
Japan's chief government spokesman Yoshihide Suga said that a government taskforce had been established to deal with the quake and tsunami, and called on people in affected areas to evacuate, according to media outlet NHK.
NHK also reported that water could be seen moving bath and forth in Onahama Port and that tide levels were rising in some areas on Japan's eastern coast. Television footage showed ships moving out to sea from Fukushima harbors as tsunami warning signals wailed.
7.3 FUKUSHIMA! Powerful Earthquake Strikes Off Northeast Japan! TSUNAMI WARNING!:
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