A strong earthquake of magnitude 5.9 shook north-eastern Japan today, followed by at least three large aftershocks.
There was no danger of a tsunami, the Meteorological Agency said.
The quake struck at 1.37pm (4.37am Irish time), centred about 20 miles below the seabed in the Pacific Ocean just off the coast of Ibaraki prefecture (state), the agency said.
It was followed by two magnitude 5.0 aftershocks, one at 2.38pm (5.38am Irish time) and the other three minutes later at the same location, the agency said. A 5.3-magnitude aftershock followed at 3.10pm (6.10am Irish time) at a slightly shallower depth, the agency said.
There were no immediate reports of injuries or damage from the quake, local police said.
Ibaraki is about 80 miles north-east of Tokyo.
The tremors also were felt in the north-eastern prefectures (states) of Fukushima and Miyagi, but hardly felt in Tokyo.
Japan sits on four tectonic plates and is one of the world’s most earthquake-prone countries.