© U.S. GEOLOGICAL SURVEY
The shallow magnitude-6.0 quake hit at 12:58 a.m. 170 km east-northeast of Miyako, Iwate Prefecture, the U.S. Geological Survey said. It was followed by a magnitude-5.3 aftershock.
The Meteorological Agency, which logged the quake's magnitude at 5.9, said there was no threat of tsunami.
The temblor struck seven hours after another magnitude-6.0 quake struck the same area on Saturday, and followed a 5.3-magnitude jolt due east of Miyako on Friday.
Japan sits at the junction of four tectonic plates and experiences a number of relatively violent quakes every year. Rigid building codes and strict enforcement mean even strong tremors often do little damage.
In April, two strong quakes hit Kumamoto Prefecture, followed by more than 1,700 aftershocks, leaving 49 dead and causing widespread damage.
A massive undersea quake in March 2011 sent tsunami barreling into the coast of the Tohoku region, leaving more than 18,000 people dead or missing, and tipping three reactors into meltdown at the Fukushima No. 1 nuclear power plant.
Comment: Seismic activity seems to be increasing worldwide recently. Also within the past week 6.4 and 7.3 magnitude quakes have struck near South Georgia island; while Queensland experienced a 5.8 magnitude earthquake - the 'biggest in 20 years'.