8.0 Magnitude Earthquake hits Alaska

ALEUTIAN ISLANDS (CBS SF) — A tsunami warning has been issued for parts of Alaska after a magnitude 8.0 earthquake was recorded near Little Sitkin Island. Additional aftershocks as large as magnitude 5.9 and 6.0 continue to rock the Aleutian Islands, some closer to populated areas.

Tsunami.gov issued the alert for coastal areas of Alaska, warning that “significant inundation is possible or is already occurring.” Residents of the area were being warned to move inland, or to higher ground.

Seismographs originally measured the quake as a 7.1 but the U.S. Geological Survey quickly upgraded that number to an 8.0. That’s a departure from the usual pattern where quakes are more often downgraded. An 8.0 quake is exponentially stronger.

The extreme depth of the quake at 68 miles deep prevented a more widespread Pacific-wide tsunami.

The Pacific Tsunami Warning Center does warn that some coastal areas in Alaska and the Northwest may experience “non-destructive sea level changes” for several hours.
The earthquake was reported at 11:53 a.m. local time.

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

Alaska is prone to the most devastating tsunamis known. This year marks the 50th anniversary of the 1964 earthquake and tsunami that destroyed so much of Alaska, and sent a series of deadly waves down the coast, wiping out much of Crescent City, California.

One of the largest mega-waves ever recorded–at 1,720 feet–devastated Alaska’s Lituya Bay in 1958. The height of the wave was measured by the devastation on both sides of the headlands, where trees were stripped or ripped from their roots. The inlet has a shape nearly perfectly constructed to amplify the power of massive earthquakes, in addition to the glacial activity following an earthquake creating massive landslides and glacial calving.

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