The earthquake and tsunami ravaged region of northern Japan suffered its worst aftershock since the March 11 quake, when a 7.4 magnitude aftershock hit just offshore. Buildings as far away as Tokyo shook for more than a minute, and a tsunami warning has been issued for a wave up to six feet high.

Although power outages have occurred in Fukushima and Yamagata, Kyodo News service is reporting no new "abnormalities" at any of the region's nuclear power facilities.