A 7.4-magnitude aftershock hit Japan about two hours ago, and less than a month after the country was devastated by a 9.0 earthquake and tsunami.

The aftershock hit 30 miles off the coast of the Miyagi prefecture– under the water– and prompted a tsunami warning, which was canceled 90 minutes later.

According to the AP, officials at the damaged Fukushima Dai-ichi nuclear plant reported there was no immediate sign of new problems caused by the aftershock.

Reports say that buildings in cities as far as Tokyo were shaking for up to a minute.

The US Geological Service reports that, in addition to this 7.4 earthquake, the same region has been struck with four 4.6-magnitude earthquakes, one 4.7-magnitude, and a 4.9-magnitude earthquake as well.