Alaska Earthquake Awareness

BY DONN LISTON

Living in a part of the world where earthquakes are a frequent occurrence requires an understanding of what causes them and how to deal with what results when the earth starts shaking violently.

My Library on November 30, 2018

Much has been learned about earthquakes since Alaska’s Big One, and some of us have faith in our survival when they occur.

Check out most recent Alaska Earthquakes here:  https://earthquake.alaska.edu/earthquakes/recent_list

For me, aftershocks from a major earthquake can be particularly unnerving. The Big One was my first major earthquake–the most massive earthquake in North American history– on March 27, 1964, at 5:36 p.m. local time. The magnitude was 9.2,
with the epicenter in the Prince William Sound region of the new state. This was the second largest earthquake ever recorded, next to the M9.5 earthquake in Chile in 1960.¹

My Response

I doubt I could tell the difference between a 9.2 and a 9.5 earthquake; after all these years only I know that it the Big One lasted longer than our recent 7.0 shaker, but I don’t think that the jerking was more intense.

Click to read about the best thing about Los Anchorage

For background: My father had come to Alaska from New Mexico to work as a civilian contractor on the White Alice System. In the 1964 quake, my two siblings, stepmother, and I were residing in a second story two-bedroom, in our Martin
Arms apartment, located on a bluff which later would be mined for aggregate at 3rd Avenue and Unga Street. The solid ground under those 26 old, wooden buildings in this military-style barracks complex, assured they were well-shaken, and the brick chimneys of the various laundry facilities collapsed, but no sliding occurred and nobody there was hurt.

4th Avenue where I sold newspapers.

When the
Big One struck, my father was many bush-plane-accessible-only miles away from
Anchorage, playing chess with another fellow on a Good Friday evening away from
their families. Pieces on the checkerboard were rattled slightly, but soon
every person at that site was extremely alarmed. A ham radio operator, who
apparently was broadcasting from the Turnagain Heights neighborhood, reported
that Anchorage had been leveled and few survivors were expected to be found.
This upper-class neighborhood overlooking Turnagain Arm was devastated as the
glacier silt base near the water’s edge lost form and slid, causing one square
kilometer to sink with 75 homes.² Today that area includes an informative
walking trail at Earthquake Park.

As a
military outpost, with both Fort Richardson Army Post, and Elmendorf Airforce
Base, Anchorage was immediately placed under martial law and residents were
urged to shelter in place. Soldiers blocked off the downtown area, and no
looting occurred.

Additionally, nobody could have known how this
event would change the way science and technology encounter the challenge of
future earthquakes and tsunamis. Mankind has learned a lot from that
earthquake.

According
to the U.S. Geological Survey: At that time, scientists did not yet know precisely
how or why the earthquake occurred.

Three
U.S. Geological Survey (USGS) scientists were immediately sent to Alaska to
figure it out. What they found marked a turning point in earthquake research.
This event helped confirm the theory of plate tectonics and provided firsthand
insight on earthquake processes, tsunami generation, and the impacts of these
phenomena on communities, both locally and across the Pacific.³

The 1964
earthquake validated a primary tenet of plate motion, according to researchers
Michael E. West, Peter J. Haeussler, Natalia A. Ruppert, and Jeffrey T.
Freymueller, of the Alaska Seismic Hazards Safety Commission. This elevated
plate tectonics theory into textbook fact, and through additional research with
advanced instruments, allowed an unprecedented view into the mechanics of giant
earthquakes.

Additionally,
the 1964 Alaska earthquake also served as a wake-up call regarding local
tsunamis.

A large rock on the road near my home November 30, 2018.

Previously
it was believed that tsunamis mostly transited from the earthquake to other locations,
as did the Alaska Quake, killing people in California. We now understand that
fjord landscapes and their huge sediment loads are breeding grounds for
submarine landslides. Even modest ground motions can trigger landslides with
catastrophic tsunami consequences. Recognition of different local sources of
tsunami generation makes the 1964 earthquake a watershed moment in revelations
about coastal hazards.

According
to the researchers above: “Almost everywhere, the greatest damages were
sustained, not from the direct ground shaking, but from soil failure, tsunamis,
landslides, and even avalanches. Alaska’s infrastructure in 1964 was, by
happenstance, relatively resilient. Wood
frame construction, lowrise
structures, and modest urban density limited fatalities from the quake itself.”

This
created new realities of Alaska living. The 7.0 earthquake of November 30 could
be considered by some as just a late-breaking aftershock. Over 54 years those
of us who have lived here continuously have grown accustomed to earthquakes. We
call them tremors. They serve as a reminder that the earth can become animated
without notice.

And I
still avoid staying very long in tall buildings.

Sources:

Alaska
Earthquake Facts: http://earthquake.usgs.gov/earthquakes/events/alaska1964/

Anchorage
Devastation: GeoScienceWorld, “Why the 1964 Great Alaska Earthquake Matters 50
Years Later, http://srl.geoscienceworld.org/content/85/2/245.full

https://earthquake.usgs.gov/earthquakes/events/alaska1964/

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