A major earthquake measuring 7.2 on the Richter scale has struck islands off northern Japan, but no tsunami alert has been issued.According to the US Geological Survey (USGS), the quake occurred at 03:05 GMT on Friday near the Russian-administered Kuril island chain, 1,490 (about 925 miles) kilometers north of the Japanese capital, Tokyo. The tremor hit at a depth of 122 kilometers (about 76 miles), the USGS said. The quake also shook towns in Japan’s Hokkaido Prefecture. “We have received no reports of damage so far,” said a spokesman at the Hokkaido police, adding there were no reports of injuries. On Saturday, nearly two dozen people were injured after a 6.3 magnitude quake hit an area near Awaji Island in Hyogo Prefecture. Earthquakes are common in Japan, which sits on the Pacific Ring of Fire, where the meeting of four tectonic plates causes high seismic activity. On March 11, 2011, Japan was hit by a 9.0-magnitude earthquake followed by a devastating tsunami that ravaged through the country’s northeastern coast. The waves from the tsunami, which hit the Fukushima Daiichi nuclear plant 45 minutes after the quake, shut down the backup generators at the facility. The early damage disabled the reactor’s cooling system, leading to meltdown, explosions and radiation leaks. The Fukushima Daiichi plant has leaked radiation into air, soil and the Pacific Ocean ever since it was hit by the massive earthquake and tsunami.