Magnitude 6.6 Earthquake Hits Japan (Updated)

Japan's been struck with another earthquake, right smack in its center. Details are scant, but the immediate worry is if damage has rippled outward to already damaged and internally sensitive nuclear plants bruised by March's quake.

The USGS says the quake's epicenter is 89 miles from Honshu—at sea—which puts it 364 miles from Tokyo proper. No word on a tsunami threat yet. [USGS via Breaking News]

Update 3:56 PM EST: The Pacific Tsunami Center says no tsunami warning will be issued. This is an enormous relief.