An earthquake measuring a magnitude 7.9 struck the western Aleutians, early Monday afternoon at 12:53 pm, triggering Tsunami warnings throughout the immediate area from Nikolski to Attu and a tsunami evaluation for all other coastal areas in the state and beyond.

The earthquake was generated at a depth of 66.8 miles according to the Earthquake Hazard Program at USGS, and occurred 15 miles Southeast of Little Sitkin Island.

The quake was felt as far away as the southern Kenai peninsula. But, by the time it reached that area over 1,200 miles away, the shaker was but a small fraction of its intensity. The quake was felt as an almost imperceptible slow rocking motion in the east to west direction.

USGS stated on their site that the quake “occurred as the result of oblique normal faulting at moderate depths. At the location of this event, the Pacific plate subducts northward beneath the North America plate at a rate of approximately 59 mm/yr. The mechanism, location, and depth of the June 23 event indicate that the earthquake likely occurred within the subducting Pacific plate, several kilometers beneath the slab interface.”

As many as 17 aftershocks were felt after the initial shaker. The aftershocks lessened in intensity with the strongest being 6.0 about an hour later. This earthquake is the largest so far this year to occur in this area.

There were no  reports of damage from the quake or its aftershocks, but a Tsunami warning prompted the evacuation of communities in the region. Adak residents took to the hills as a precaution, moving to their evacuation center on Bering Hill.

Although a small wave of about seven inches occurred at Amchitka, the wave lessened the further it moved from its source.

The Tsunami warning was cancelled by late afternoon.

The island closest to the source of the quake and its swarm of aftershocks, Little Sitkin Island, is a six mile wide island in the Rat Island archipelago. The entire island itself is a large stratovolcano that last erupted in 1900 and is uninhabited.

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