Friday, March 27, 2015

Anniversary of Alaska's Good Friday Earthquake

Today is another anniversary of an event I include in my geology lectures, the 1964 Good Friday Alaska Earthquake.  In the interest of showing instead of telling, I'll let Accuweather's latest installment of Weather History do my work.
On March 27th, 1964 at 5:36 PM AST, a 9.2 M megathrust earthquake tossed south-central Alaska.
ETA: Accuweather has since deleted this video, so I am replacing it with 1964 Quake: The Great Alaska Earthquake from the United State Geologic Survey.

"1964 Quake: The Great Alaska Earthquake" is an eleven minute video highlighting the impacts and effects of America's largest recorded earthquake. It is an expanded version of the four minute video "Magnitude 9.2". Both were created as part of USGS activities acknowledging the fifty year anniversary of the quake on March 27, 2014. The video features USGS geologist George Plafker, who, in the 1960's, correctly interpreted the quake as a subduction zone event. This was a great leap forward in resolving key mechanisms of the developing theory of plate tectonics. Landslide impacts and the extreme tsunami threat posed by these quakes are also discussed. Loss of life and destruction from the earthquake and accompanying tsunamis was the impetus for things like the NOAA Tsunami Warning Centers and the USGS Earthquake Hazards Program.
This story ranks right up there with my recounting of the 1994 Northridge Earthquake in its importance to my lecture about seismology.  In particular, it features two phenomena the Northridge Earthquake, a tsunami, which the Accuweather video depicts, and liquifaction, which it glosses over.  That latter process resulted in the Turnagain Heights landslide.  I show my students the photo below of it and recount a story I first read in National Geographic about a woman who escaped from her house in that neighborhood, setting her children on the top of each slump scarp then climbing up after them, all as the slump blocks continued to slide down and out to sea.  It certainly personalizes the disaster for my students.

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