A powerful 6.6 magnitude earthquake struck Wednesday off the coast of Vanuatu in the South Pacific, but US geologists said it was too deep to cause a tsunami.

The US Geological Survey said the quake struck at 1603 GMT about 37 kilometers (23 miles) west of Sola, Vanuatu.

The National Tsunami Warning Center in Palmer, Alaska said that the New Year's Day temblor, with a depth of 195 kilometers, was "located too deep within the earth" to generate a sizeable tidal wave.

A 5.1-magnitude quake hits eastern Japan: USGS
Tokyo (AFP) Dec 31, 2013 - A shallow 5.1-magnitude earthquake hit eastern Japan Tuesday, the US Geological Survey said, but there were no local reports of any damage.

The quake hit at 10:03 am (0103 GMT) in Ibaraki prefecture, 146 kilometres (91 miles) northeast of Tokyo, the agency said.

The tremor was 9.9 kilometres deep, the agency said.

Located roughly 80 kilometres southwest of the Fukushima nuclear plant, the quake was strong enough to gently rock high-rise buildings in the capital.

Japan Meteorological Agency earlier estimated the quake's magnitude at 5.4.

It was followed eight minutes later by a very shallow 3.6-magnitude quake in the same area, according to the Japanese agency.

Tokyo Electric Power said the quakes did not affect the Fukushima plant, where crews are working through the holiday season to cool reactors crippled by the 2011 tsunami.