Japan was hit by an earthquake off the coast of Fukushima, which was devastated by a tsunami triggered by a 9.0 quake five years ago.
Experts say it was in fact an aftershock relating to that first devastating quake in 2011
"The first earthquake was such a large earthquake that there was an expansive rupture zone. So this earthquake still resides in that rupture zone and that’s why they consider it to be an aftershock," USGS Geophysicist Julie Dutton said.
"The larger earthquakes, you can see aftershocks occur weeks, months, and even years later because that stress regime is still releasing pressure and readjusting to the original mainshock."
Tsunami warnings were issued following this latest quake, which was a 7.4, but these have since been removed. However, the Japan Meteorological Agency is warning that another large quake is expected within the next few days and people in the region have been advised to ‘remain cautious’.
The quake happened at 5.59am local time and waves at Sendai port reached 1.4 metres. Flights to Sendai airport have been disrupted.
Several people are reported to have suffered minor injuries, but no deaths have been recorded.
