Monday, June 23, 2014

Quake hits off Alaska's Aleutian Islands

Quake hits off Alaska's Aleutian Islands

JUNEAU Alaska Mon Jun 23, 2014 8:14pm EDT

(Reuters) - A magnitude 8.0 earthquake struck deep under the ocean floor near Alaska's Aleutian Islands, triggering shaking that could be felt for vast distances and prompting a tsunami warning, the U.S. Geological Survey and National Tsunami Warning Center said.
The tsunami warning, later downgraded to an advisory, prompted the evacuation of about 150 residents of the town of Adak to higher ground, according to media reports. It was not immediately clear whether the quake caused injuries or damage.
The quake was so large and deep that it triggered dozens of aftershocks within an hour and prompted enough shaking that it will be picked up by seismometers around the world over the next 24 hours, said Mike West, a seismologist who serves as director of the Alaska Earthquake Center.
"When you've got an earthquake that big, it rings the Earth like a bell," West said.
The warning covered coastal areas of Alaska from Nikolski to Attu, officials said, adding that the level of tsunami danger was being evaluated for other U.S. and Canadian Pacific coastal areas.
The U.S. National Oceanic and Atmospheric Administration initially warned of widespread, dangerous coastal flooding and powerful currents in the region for hours in the event of a tsunami. The warning was downgraded about two hours after the earthquake hit.
A tsunami advisory, less severe than a warning, was in effect for coastal areas of Alaska from Unimak Pass to Nikolski.
The quake struck shortly before 1 p.m. (1700 ET), about 14 miles (23 km) southeast of Little Sitkin Island, Alaska, at a depth of about 71 miles (114 km), the USGS said.
Tsunamis are waves resulting from undersea quakes that can measure several yards (meters) high and can overwhelm coastal areas near and far, NOAA said. It takes a large quake of magnitude 7.0 or higher to produce a tsunami, the center said.
In 2004, a tsunami produced by a magnitude 9.3 undersea earthquake struck near Indonesia and 240,000 people were killed, the center noted.

(Additional reporting by Eric Beech in Washington; Writing by Sharon Bernstein in Sacramento; Editing by Jim Loney amd Will Dunham)

7.9 Earthquake Shakes Aleutians, Prompts Tsunami Warning

8.0 magnitude earthequake Monday afternoon prompts warnings for Aleutian residents, fishermen

Austin Baird Austin Baird, Political, Rural Reporter,
POSTED: 01:41 PM AKDT Jun 23, 2014    UPDATED: 04:36 PM AKDT Jun 23, 2014 
A massive earthquake near a far-western, uninhabited Aleutian island prompted a tsunami warning Monday afternoon that stretched across hundreds of miles of sea.
The epicenter of the 7.9 magnitude earthquake was amid the Rat Islands, making it tied for the eighth largest recorded in U.S. history, according to U.S. Geological Survey records.
While the quake was huge, officials from the Tsunami Warning Center in Palmer said that "it's not looking like it's a significant height in the wave."
But the size of a wave does not necessarily reveal its potential to cause damage.
"You don't need much more than about 6 inches of water moving at a significant speed to pull you out, but this is the entire ocean moving," said Scott Langley, an electronics technician with the Tsunami Warning Center. "It doesn't take a lot of height in waves to do damage."
The National Weather Service and U.S. Coast Guard put out alerts to fishermen who could be thrown off course by waves or unexpected currents. Langley said fishermen near land are likeliest to be at high risk.
There were no immediate reports of distressed fishermen, though.
"We've gotten no calls from anyone," said Coast Guard Petty Officer Shawn Eggert. "All we're doing is issuing warnings and preparing Coast Guard cutters and other assets."
And with the remote location, borough officials and Aleutian residents reported no obvious damage.
"No one reported feeling anything, much less experiencing any damage," said Laura Tanis, Aleutian East Borough spokesperson. The borough is composed of King Cove, Cold Bay, False Pass, Akutan, Nelson Lagoon and Sand Point, all slightly east of the area covered by the advisory.
Officials caution anyone in an area impacted by an advisory or warning to stay away from the coast and to move to higher ground. Everyone is warned to listen to local emergency officials for the latest information.
8.0 magnitude earthquakes occur approximately every 10 years along the Aleutian arc, according to the Institute of Marine Sciences at the University of Alaska Fairbanks.
USGS records show that similarly-sized earthquakes occurred in the Aleutians in 1938, 1946, 1957, 1965, 1986, 1996 and 2003. 
The largest was in 1965, when an 8.7 magnitude earthquake hit in nearly the exact same area as the Monday earthquake.
Amchitka Island, 25 miles southeast of the most recent epicenter, was used for three underground nuclear detonations from 1965 to 1971.
The area is still studied by scientists who want to know if groundwater near the detonation sites may carry radioactive materials toward the ocean.

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  1. PzFeed Top News ‏@PzFeed
    Strong 6.9-magnitude aftershock hits the Aleutian Islands in Alaska after earlier 7.9 quake - USGS