Just before 8:30 a.m. local time on November 30, a magnitude 7 earthquake rattled southern Alaska. The waves rumbled from an epicenter just eight miles north of Anchorage, the state's most populated city—downing power lines, collapsing roads, and sending people fleeing for cover. A tsunami warning was issued soon after the shaking started, but it was lifted by 10:00 a.m. local time.

The quake was “certainly a pretty big one,” says Ben Andrews, the director of the Smithsonian's Global Volcanism Program. So far, reports suggest that the earthquake and its aftershocks were tough on the region's infrastructure, but very few fatalities are expected, in part because Alaska is prepared for such an event.

The region is the