The biggest earthquake was located in the Pacific Ocean off the northern island of Hokkaido. It registered 6.1 on the Richter scale and shook buildings on the eastern side of the island. An aftershock with a 4.3 intensity was later recorded in the same area.
Fukushima Prefecture experienced a 4.6 earthquake, which was also centered in the ocean. Fukushima houses the Daiichi nuclear power plant that exploded 10 years ago. No further damage was reported and there was no danger of a tsunami.
The largest of the three earthquakes that struck Chiba registered 3.9 on the Richter scale and 3 on the Japanese intensity scale. The epicenter was approximately 50 kms east of Tokyo.