Learning together through history

Anchorage observes the 1964 Earthquake’s 50th anniversary.

At exactly 5:36 p.m. the museum’s proceedings had come to a pause, and the host speaker asked the crowd for four minutes of silence — the length of the earthquake, in honor of those impacted by it. Footage of Anchorage on the day of the earthquake played for attendees over a projector while they reflected, a visual trip to a place and time that lives on through us today.
Those who filled the Anchorage Museum’s Auditorium last Thursday joined many others across the state and throughout the world in remembering the Great Alaskan Earthquake of 1964. Residents and community leaders from some of Alaska’s hardest-hit communities by the earthquake and resulting tsunami took to the podium to share their experiences.
Appearing in a pre-recorded video, Sen. Lisa Murkowski aptly captured the tone of the commemoration’s first half.

Did you know?

Geologists today commonly use the Moment Magnitude Scale to measure the size of earthquakes accurately. Improvements in seismometer technology were made after the 1964 quake which made recording low-frequencies possible. This is partly why the 1964 quake’s initial rating of 8.6 (Richter Scale) was changed to 9.2 (MMS); the figure we use today.

“It’s hard to find a silver lining, but if there is one, it’s that we came together,” Murkowski said.
While powerfully devastating, the Great Quake also left behind signs of its existence that are open to interpretation. A flood-line exists in Valdez that marks the tsunamis deadly reach. A dock in Prince William Sound was rendered useless without sufficient water or land beneath it. Look left at the gas station just before Girdwood and one can see bleach-white trees jutting forth from the flats.
The most noticeable evidence of the earthquake that we can see today is that of the ground sinking. Take the trees for an example.
“High tide is a completely different thing for next few hundred years because it takes a long time for the land to start rising back up,” said Jennifer Witter, who is an assistant professor of geological sciences with UAA. “Girdwood had to be relocated, Portage had to be relocated because they were suddenly in the tide zone.”
When the 9.2 magnitude quake hit, part of the Girdwood costal area dropped below sea level, letting saltwater in which killed the trees and left them in a state of driftwood limbo. They rise as the land rises over time, creating a ‘ghost forest’.
“In many ways, what we know about these giant mega-thrust earthquakes today is understood in the shadow of what was learned from the 1964 earthquake,” U.S. Geological Survey geologist Peter Haeussler explained to the crowd at the Anchorage Museum on Thursday. “As a result of what was learned from 1964, some geologists that had been working in the Pacific Northwest had visited Alaska and were like, oh, ghost forests, we’ve got these down here too.”
After seeing the similarities in the trees, geologists reasoned that costal Oregon and Washington likely faced the same tsunami hazards as Alaska. This was a critical moment of discovery, as the last 1964-like earthquake near the Oregon-Washington border happened around the year 1700.
After the 1964 quake, science changed. New geological techniques were developed, and plate tectonic theory was more broadly substantiated. The relationship between earthquakes and tsunamis was made more explicit than ever before, which lead to an increase in the sophistication of tsunami warning centers across the world. The language of earthquakes was forever changed.
As Haeussler continued his lecture for the diverse, attentive museum crowd, one brief moment stood out amongst the rest.
“This gets to the place of this earthquake in the history of plate tectonic theory,” Haeussler said, referring to 1964. “And they may sound like ethereal words, and I was actually surprised to hear Lisa Murkowski use the term ‘plate tectonics’ out there in her speech today. Good to hear a politician with a vocabulary,” he said jokingly.
The crowd laughed.


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