Watch CBS News

Powerful Aftershocks Strike Following 7.9 Magnitude Alaska Earthquake

(CBS SF) - A massive 7.9 magnitude earthquake Monday in the Aleutian Islands was quickly followed by smaller 5.9 and 6.0 quakes closer to land.

The original quake set off a Tsunami warning after striking deep in the water east of Little Sitkin Island. That was quickly followed by a handful of smaller quakes closer to land. Those tremors ranged in size from magnitude 3.7 to 6.0. All were centered at least 100 kilometers beneath the Earth's surface.

A magnitude 6.9 earthquake struck the area around 6 p.m. Pacific Time.

Seismographs originally measured the initial quake as a 7.1 but the U.S. Geological Survey quickly upgraded that number to an 7.9. That's a departure from the usual pattern where quakes are more often downgraded.

PREPARING FOR TSUNAMIS: California Harbors Improve Mega Wave Protections
WEST COAST MEGA-QUAKE: Faults Off Coast Greater Risk Than San Andreas
NEW TECH GIVES WARNINGS: 30-Second Warning Before Quakes
TSUNAMI RADIATION: Kelp Holds Clues To Fallout From Japan Quake
RADIATION FEARS: Internet Postings Stoke Concerns

Another massive quake registering 6.9 struck just before the Alaska quake, this one on the polar opposite side of the ocean, north of New Zealand.

View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive reporting.