The quake struck in the Pacific Ocean 245 kilometers off the coast at 5:18 p.m. local time on Friday, at a depth of around 35 kilometers.
prompted a tsunami warning on where last year’s devastating quake triggered a tsunami and multiple meltdowns at the Fukushima Daiichi nuclear plant.
The U.S. Geological Survey initially put the quake’s strength at 7.4-magnitude, but later revised its estimation, lowering it to 7.3.
A 6.2-magnitude aftershock was experienced just minutes after the initial quake.
Speaking of the initial quake, Randy Baldwin, of the U.S. Geological Survey, said "this may be considered an aftershock itself," from the 2011 temblor, as the tectonic plates under the region are still settling into place.
television broke off regular programming to warn that a strong quake was due to hit, shortly before the earthquake struck. Shortly afterwards, the announcer urged people near the northeast coast to flee to higher ground.
Buildings in Tokyo reportedly swayed for at least several minutes as the quake struck.
had problems contacting each other during the quake as phone lines were overloaded. In Miyagi, the phone operator said, "Owing to the recent earthquake, phone lines are very busy, please try again later."
tsunami struck Japan’s Miyagi prefecture, the location of the ravaged Fukushima nuclear plant. However, authorities reported no damage, and radiation levels at Fukushima reportedly remain stable.