Magnitude 6.2 Earthquake Hits Eastern Aleutians
Friday, August 10 2012
A large earthquake hit near Nikolski around 10:30 Friday morning.
“Nikolski is located about 75 miles from the epicenter and I would expect that at this distance a 6.2 would be felt by most people," says Alaska Earthquake Information Center seismologist Natasha Ruppert. "But when we called and asked people, nobody actually felt it.”
Ruppert says she hasn’t had time to do any analysis, but her suspicion is that the earthquake, although powerful, moved very slowly – too slowly for human perception.
“When an earthquake is initiated, it starts in one point, then this rupture propagates along the fault. It can be slow propagation and then it would generate more low frequencies in the seismic wave."
Despite that, Ruppert says the quake probably created a good-size fault.
“It’s probably on the order of 10 miles, so it’s a pretty sizeable earthquake."
The last time a magnitude 6-plus earthquake hit the eastern Aleutians was September 2011.
So far, few aftershocks have been recorded from this morning’s event. Ruppert expects there will be some, although people may not feel them either. The earthquake didn’t generate a tsunami warning.
TripleU on Sunday, August 12 2012:
Please – before continuing to hype and scare the community with the Tsunami Warning reference for the City of Unalaska– get some answers from the scientists at NOAA. NOAA explains the difference in the 2 coasts of our island…… it seems the City of Unalaska Police department does not follow up to get the specifics on which coast is affected i.e. the Pacific coast or Bering Sea coast when they receive the “Aleutian Island” Tsunami Warning from NOAA or the National Warning System, Emergency Alert System.
Yet if you speak directly with NOAA or the Alaska department of Homeland Security and Emergency Management they will say Tsunami warnings refer to the Pacific ocean side of the Aleutians only.
The NOAA web site below explains more about the Bering sea advisories here:
http://wcatwc.arh.noaa.gov/faq/ArcticTalkingPoints.htm
Why only advisories for these coasts?: Due to the extensive shelf, lack of major tsunami sources, historical tsunami information, and relatively shallow near-coast waters, large inundating tsunamis are not expected along the Bering Sea and Arctic coasts.
Appropriate response: The appropriate response for a tsunami advisory is to move away from the immediate shoreline, off the beach, and out of the water. Large scale evacuations are not necessary.
Earthquake on Friday, August 10 2012:
This should remind people to be more aware. They should really reconsider if they continue to go about their day ignoring the Earth, in their minds, thinking about work, what to do next, watching a big game, going to the movies, shopping, etc.