An earthquake of 5.6 magnitude struck Japan on Tuesday, the Japan Meteorological Agency said. No tsunami warning has been issued. Officials said the temblor originated at a depth of about 50 kilometers off the coast of Fukushima Prefecture, which has the Fukushima Daiichi nuclear plant.

Operators of the Fukushima Daiichi, Fukushima Daini and the Onagawa plant in Miyagi said no problems were encountered after the quake, The Mainichi reported. The National Police Agency said no casualties have been reported so far, Japan Today reported.

On March 11, 2011, an earthquake of magnitude 9 triggered a massive tsunami off the country’s coast that led to the world’s worst nuclear disaster after Chernobyl. All reactors in the Fukushima Daiichi nuclear plant (pictured above) were shut down after the incident, but cooling is still required for the nuclear fuel stored at the site.

Japan lies in a seismically active zone and accounts for 20% of the world’s earthquakes.