An unusual sequence of earthquakes is striking an area about 20 miles east of Saint George Island in the Pribilofs. Since Friday evening, January 31, five earthquakes over magnitude 5.0 have occurred with the largest at magnitude 5.4. No reports of damage have been received from St. George, though residents of both St. George and St. Paul report feeling the quakes.
Very little historical seismicity is known in this area. The U.S. Geological Survey (USGS) earthquake catalog shows no earthquakes over magnitude 5 occurring in the region of the present swarm, though one magnitude 6.7 earthquake occurred in 1991, about 250 miles northwest of St. George, and triggered a minor tsunami recorded in Adak and Dutch Harbor.
The National Tsunami Warning Center in Palmer, Alaska and NOAA NWS Tsunami.Gov are monitoring this series of earthquakes. Should a stronger quake occur, at or above a magnitude 7.0, a threat for a tsunami will be rapidly evaluated for the Pribilof Islands and for the Aleutian Islands from Unimak Pass to Attu.
There is no way to tell if the present sequence is precursory to a larger earthquake, or is a swarm of earthquakes which will not lead to a larger event.
For more information on your tsunami threat and to monitor these quakes, head to
http://ntwc.arh.noaa.gov/ and sign up for Tsunami Alerts on Twitter at @NWS_NTWC.
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