Unalaska, AK – An 8.1-magnitude earthquake near Russia's Kuril Islands, west of the Aleutians, triggered a tsunami warning throughout coastal Alaska Friday evening. A wave was measured at about 27 inches on the western Aleutian island of Shemya, but Friday's tsunami was of negligible size by the time it reached the Eastern Aleutians.

Communities in coastal Alaska were on watch for about three hours starting at 7:33 p.m. The Unalaska Department of Public Safety called in all of its officers, as well as many volunteer firefighters and EMTs, who waited at the ready until the warning was called off at 10:30 p.m. The residents of Nikolski, a village located in a low-lying coastal area of nearby Umnak Island, evacuated to higher ground.

Bruce Turner, the science officer at the West Coast and Alaska Tsunami Warning Center in Palmer, says that the earthquake was large enough to cause concern, but mostly just in the immediate vicinity of the quake.

The Tsunami Warning Center issues regionwide tsunami warnings following any earthquake with a magnitude greater than 7.4, but the odds of a tsunami originating in the western North Pacific doing any damage to communities in the Aleutians are pretty slim. The few island communities are all on the Bering Sea side of the chain, in places that tsunamis originating far west are unlikely to reach.

Turner says that a much greater threat is posed by tsunamis that originate nearby. That was what happened during the Alaskan earthquake of 1964, when a tsunami devastated Kodiak, and what happened in the Indian Ocean in 2004. In general, if you live in coastal Alaska and feel a quake that's large enough to knock you out of your chair, you should start running for higher ground.

Turner says that in Unalaska, the risk is that a nearby earthquake would create a landslide somewhere along the shoreline heading out to Summer Bay, which could create a tsunami event in Unalaska Bay.

Friday's incident was similar to one that happened a month ago, when a quake in almost the exact same place caused a slightly larger wave to form. That tsunami also had no impact on Unalaska, but it did do minor damage to docks and boats in Crescent City, California, where the wave was measured at about 5 feet 9 inches.