Tokyo was hit by its second quake in three days today, giving the capital's skyscrapers a shake but there were no reports of damage or casualties.
The 4.8 magnitude jolt struck Tokyo and areas of eastern Japan at 12:57 pm (local time), the US Geological Survey said, after a 5.0 magnitude earthquake shook the capital on Sunday.
The temblor's epicentre had a relatively shallow depth of about 23 kilometres in Chiba, east of Tokyo, the USGS said.
There was no threat of tsunami.
Japan sits at the junction of four tectonic plates and experiences a number of relatively violent quakes every year, but rigid building codes and strict enforcement mean even powerful tremors frequently do little damage.
A massive undersea quake that hit in March 2011 sent a tsunami barrelling into Japan's northeast coast, leaving more than 18,000 people dead or missing, and sending three reactors into meltdown at the Fukushima nuclear plant.
