A magnitude 5.6 earthquake, which measured a strong 5 on Japan's intensity scale, struck at a depth of 20 kilometers off the coast of Iwate Prefecture on Friday at 11:25 p.m.
No tsunami warning was issued.
The Japan Meteorological Agency said the temblor occurred in waters off the prefecture's northern coast at a depth of 18 kilometers below the seabed. The magnitude of the quake was revised upward later from an initial estimate of 5.5.
In Iwate Prefecture, a temporary blackout hit around 2,200 households after the quake.
Friday's temblor followed a magnitude 7.4 quake off the coast of Fukushima Prefecture on Wednesday night that left at least three people killed and many more and 180 injured.
It caused widespread power outages, transport disruptions and factory suspensions.
The weather agency said early Saturday that the two temblors are likely to be unrelated, but details remain unknown.
- Detailed information about this earthquake from the Yahoo! Japan Weather & Disaster website
- Detailed information about this earthquake from the Japan Meteorological Agency website
- The Japan Meterological Agency website
- An explanation of shindo, Japan's earthquake intensity scale.
- A guide to what to do before, during and after an earthquake.
- Our portal for disaster-related information