The tremor, which hit just before midnight, hit at a depth of around 10 kilometres (six miles), around 39 kilometres south of Shizuoka and 165 kilometres south of Tokyo, the US Geological Survey said.
It had initially put the magnitude at 5.9.
The epicentre of the quake was a considerable distance from the 9.0-magnitude earthquake that rocked Japan on March 11, generating a massive tsunami that wiped out whole stretches of the country`s northeast coast, leaving more than 20,000 people dead or missing.
Thousands more were made homeless when a nuclear reactor began melting down after its cooling systems were swamped by the waves in the worst atomic disaster the world has seen for a quarter of a century.
Japan, located at the junction of four tectonic plates, experiences 20 percent of the strongest quakes recorded on Earth each year. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
