A strong earthquake with a preliminary magnitude of 5.3 struck northeastern Japan on Thursday, without reports on casualties, damage or tsunami warnings, the Japan Meteorological Agency said. The operator of the crippled Fukushima Daiichi nuclear power plant said there were no signs of abnormalities at the facilities from the quake. The focus of the tremor was off the coast of Fukushima Prefecture, about 250 km north of Tokyo, at a depth of 40 km. The quake measured four on the Japanese seismic scale of seven in some areas of Fukushima, according to the agency. It defines an intensity of four as capable of causing dishes and objects in shelves rattle. The Japanese scale measures how much places were shaken on the surface while the Richter scale measures the energy of the quake itself.
Japan, located in a zone where the Eurasian, Pacific, Philippine and North American tectonic plates meet and occasionally shift, is hit by 20 percent of the world's earthquakes of magnitude six or greater. A magnitude 9.0-quake and tsunami hit the Fukushima Daiichi nuclear complex in March 2011, causing the world's worst nuclear accident since Chernobyl in 1986.