VIDEO: Strong 7.3-quake rattles east Japan, no tsunami risk
A structure falls due to an earthquake in Koorimachi, Fukushima prefecture, Japan. AP
The quake produced powerful shaking along parts of Japan's eastern coast, and was felt strongly in Tokyo, but triggered no tsunami alert.
Kyodo news agency reported at least 30 people injured, but gave no further details.
There were no immediate reports of significant damage, though local news broadcast images of a landslide on a highway.
Japan's meteorological agency said the quake hit at 11:08 pm (1408 GMT) at a depth of 60 kilometres (37 miles) in the Pacific off Fukushima -- near the epicentre of the 2011 killer quake which triggered a towering tsunami and killed more than 18,000 people.
The agency initially reported the strength of the quake as 7.1, but later revised the figure upwards. It said the quake was considered an aftershock of the massive 2011 temblor.
Aftershocks continued to rattle the region in the hours afterwards and officials cautioned local residents to be vigilant. A handful of people were reported to have sought shelter at evacuation centres.
"We are working quickly to collect information but we still have no details to announce. There were some unconfirmed reports about landslides but we are still checking," Mikihiro Meguro, an official from the Fukushima prefectural government, told reporters.
