An earthquake measuring 6.1 magnitude struck off northeastern Japan on Wednesday, the U.S. Geological Survey said.

There was no immediate tsunami warning, or reports of damage or casualties.

A series of strong quakes struck the south of Japan late last week killing nearly 50 people.

On Wednesday, survivors of the weekend 7.0 magnitude quake struggled with shortages of food and water. 

The USGS said Wednesday's quake was centred 104 kilometres east southeast of Sendai, Honshu, near where a devastating quake and tsunami struck in March 2011. It was 51 kilometres deep.

Sendai map Japan

The latest quake was centred about 100 kilometres east-southeast of Sendai. (CBC)