Alaska seismologists tell NewsLincolnCounty.com that they are still studying the large earthquake that struck the Gulf of Alaska January 23rd at 1:31am our time. The 7.9 richter was felt throughout southeastern Alaska and triggered a tsunami warning for all of southeastern Alaska and parts of Canada. A tsunami watch was cast for the entire west coast of the U.S., and down in to Central America.
Seismologists say the continued flurry of minor to medium quakes in and around the big quake’s epicenter can be expected to continue for at least a month, perhaps longer. Seismologists characterized the big shaker as a “side-slip” earthquake – a horizontal movement of the fractured sea floor. Side-slip earthquakes can be violent but since sections of the sea floor are slipping horizontally, there is little upward sea floor movement that shoves water vertically, causing a tsunami. As you can see in the above graphic that the epicenter was noticeably south of the Alaskan Subduction Zone – the dark blue curving line that reaches to nearly the east coast of Russia. An earthquake along that particular subduction zone corridor is quite famous for large tsunamis, including one that heavily damaged the south coast of Alaska back in 1964.
But again, Alaskan seismologists say they expect the pace of after-shocks from the big shaker of January 23rd to gradually subside over time. But they warn against complacency since the Alaskan Subduction Zone is active and there are predictably major earthquakes in the future of the region – earthquakes that produce tsunamis like the one in 1964 that hammered the Alaskan and Oregon Coast. In Lincoln County, a family camping at Beverly Beach State Park were crushed by logs and drowned in the tsunami. Further down the coast Crescent City, California suffered the worst loss of life outside of Alaska, with eleven deaths and the destruction of Crescent City harbor facilities.
So get your tsunami warning radios – NOAA Auto-Alert variety – and quickly learn about any tsunami threat that may be headed your way. If you’d like to take a look at NOAA Auto-Alert radios, they’re at the Electronics Superstore in Lincoln City, right across the street from Lincoln City City Hall at 800 SW 101.