TOKYO: A strong magnitude 6.1 quake hit off the east coast of Japan early on Thursday (Sep 21) but authorities did not issue a tsunami warning.
It struck 281 kilometres east of the city of Kamaishi on Honshu, the largest Japanese island, at a shallow depth of just 10 kilometres, the United States Geological Survey (USGS) said.
The Japan Meteorological Agency said no tsunami warning was in effect and the USGS said only weak shaking would have been felt on Honshu and the risk of damage was likely to be minor.
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 of them mean even strong tremors typically do little damage.
A massive undersea quake that hit in March 2011 sent a tsunami crashing 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.
It was the world's worst atomic accident since Chernobyl in 1986. The company Tokyo Electric is trying to clean up and dismantle the reactors in a process expected to last decades.