As I am sure everyone has recognized by now, one of the biggest earthquakes recorded in our planet’s history–and the biggest in the United States–rocked Alaska for some three+ minutes 50 years ago today. The 1964 Good Friday earthquake, known also as the Great Alaska earthquake, measured magnitude 9.2. The earthquake shocked the fledgling state with catastrophic environmental effects, including most notably the lateral-spreading collapse of entire neighborhoods in the capital city and a violent tsunami aimed straight at other U.S. coastlines in Washington, Oregon, California, and Hawaii.

[youtube=https://www.youtube.com/watch?v=rJOGJApz1M0]

Remarkably, at that time a mere 50 years ago the powerful theory of Plate Tectonics was just on the cusp of emerging as the paradigm of Earth science. Without that context, this earthquake was virtually inexplicable. Initially, scientists interpreted it as motion on a near-vertical fault plane, rather than on what we now recognize was a low-angle subduction megathrust where the Pacific Ocean plate plunges beneath North America. But it was scientifically great timing: data from the earthquake and its aftershocks brightly illuminated many of the key elements of Plate Tectonic theory. It enormously advanced the science.

This semicentennial anniversary has been talked about from every corner, and I have a dissertation to write, so I’ll leave my commentating there and provide you with a marvelous wealth of other online resources that have already been compiled. Sit back, marvel, and appreciate what we’ve learned:

A great, easy-to-read summary article explaining the scientific significance of this quake, from the Seismological Society of America:
http://srl.geoscienceworld.org/content/85/2/245.full

Compilation of videos, info, data, etc. by the USGS:
http://earthquake.usgs.gov/earthquakes/events/alaska1964/

USGS photo library of quake effects and damage:
http://libraryphoto.cr.usgs.gov/cgi-bin/search.cgi?search_mode=exact&selection=Alaska+Earthquake+1964%7CAlaska+Earthquake%7C1964

An extensive [geolocated!] online photo collection curated by the University of Alaska Anchorage:
http://www.64akquake.org/

Audio recordings of the earthqauke (!) presented by the Seismological Society of America. (Bonus: Mr. Robert Pate in the first recording sounds something like what Huell Howser would going through an earthquake)
http://www.seismosoc.org/publications/Alaska-EQ-Sounds.php

The earthquake has a Did-You-Feel-It map! It shows an uncommonly vast area of severe to violent shaking, centered on the capital city:
http://earthquake.usgs.gov/earthquakes/dyfi/events/ak/goodfrid/us/index.html

A harrowing tale from Turnagain Heights as the Earth literally fell apart around them:
http://www.adn.com/2014/03/22/3388654/march-27-1964-the-day-the-world.html

…and the rest in a captivating series by The Anchorage Daily News in commemoration of the quake:
http://www.adn.com/64earthquake/, including a collection of videos.

A huge blog full of eyewitness accounts:
http://alaskanearthquake1964.wordpress.com/

Info on the tsunami of ’64 and preparations today:
http://nthmp.tsunami.gov/tpw/64earthquake-tsunamis.html

…and accounts of the 1964 tsunami from the coast of Oregon:
http://www.oregonlive.com/pacific-northwest-news/index.ssf/2014/03/tsunami_generated_by_good_frid.html

Today Alaska held a drill for future earthquakes, their own ShakeOut. Prepare for yours at www.shakeout.org.