A strong earthquake with a revised magnitude of 7.0 on the Richter scale struck eastern and northeastern Japan including Fukushima Prefecture on Monday, the Japan Meteorological Agency said.
The agency issued a tsunami warning for waves up to one meter high for Ibaraki Prefecture along the Pacific coast after the 5:16 p.m. (0616 GMT) quake, but lifted it 40 minutes later.
There were “several” reports of injuries caused by the quake, public broadcaster NHK said.
“No additional problems were reported with the facilities at the radiation-leaking Fukushima Daiichi nuclear power plant” by the latest quake, according to the plant operator.
Subway services in Tokyo and Shinkansen bullet trains in the region were briefly suspended to confirm safety, but resumed operation afterwards.
The focus of the tremor was 6 k.m. from the surface of Iwaki City of Fukushima Prefecture, about 160 k.m. north of Tokyo, the weather agency said.
It initially estimated the quake’s magnitude at 7.1, but later revised it downward to 7.0.
The quake registered lower 6 on the Japanese seismic scale of 7 in some areas of Fukushima and Ibaraki prefectures.
The agency defines an intensity of lower 6 as “strong enough to make heavy furniture move and fall and wall tiles and to damage windowpanes in many buildings and cause them to fall”.
The agency defines an intensity of upper 6 as “strong enough to make most heavy and unbolted furniture move and fall.”
The Japanese scale measures how much places were shaken on the surface, while the Richter scale measures the energy of the quake itself.
Northeastern Japan was already severely affected on March 11 by a magnitude 9.0-quake and tsunami that left about 28,000 people dead or missing.
The weather agency urged people in the region to continue to be alert against powerful aftershocks.