Washington’s New Tsunami Model Based On The 1964 Alaska Earthquake

I’m old enough to remember the 1964 Alaska earthquake. It happened in the morning on Good Friday. I was getting ready to go to school when it started to happen. I was not in Alaska; I was in Burien, and we felt it, big time. 

The whole house started to shake, and my mom grabbed me, and we stood in the doorway thinking it was the safest place to be until it was done. ½ hour later I was on my way to school. 

I was just a kid, and I didn’t even think of the repercussions of that earthquake on other parts of the Western United States. At the time I didn’t even know what the word tsunami was. But the idea of a tsunami caused by an earthquake in Alaska is a reality that we in Washington state need to think about. Especially those living on the coast of Western Washington. 

What if it happens again? 

According to seattletimes.com, 
‘For the first time, state researchers have modeled the impact of a tsunami sparked by a magnitude 9.2 quake along the Alaska-Aleutian subduction zone, and they’ve found some surprises.
The modeling, released as a joint project between the Washington Emergency Management Department, the state Department of Natural Resources and others, is a first-of-its kind project.’ 

It’s the first of its kind project with computer modeling created by cooperating agencies like the Washington Emergency Management Department and The Department of Natural Resources.  

Up until this point, most of Washington state’s tsunami preparation has been based on earthquakes in the Cascadia Subduction Zone, which is located just 70 miles off the Washington coast. 

Elyssa Tappero, of the Washington State Military Department, says a tsunami from that area is a top priority for her department, “because it’s going to be so devastating, but there’s also a much smaller chance of it happening in our lifetimes,” She went on to say. “A large, distant tsunami, like one from Alaska, is much more likely to happen in our lifetimes,”   

So, what do we know? 

This new model based on the 1964 Good Friday Alaska earthquake shows us a few things. 

The first waves would arrive on Washington state coast about 3 1/2 hours after the earthquakes begins. 

The biggest waves from the tsunami would arrive at Westport in Grays County and would probably be 20 or more feet in height. 

After four hours, the waves hit Port Angeles, at 5 1/2 hours, they reach Seattle. 

At 7 hours, the waves will hit Olympia. 

On the Hood Canal you would see swells of three to four feet but the surge would be up to 14 feet at the end of the channel near Belfair at Lynch Cove. 

A tsunami wave is not just a short moment in time but could last over several hours, and up to 24 hours, and the first wave is not necessarily the biggest wave. 

What about an earthquake closer to home? 

According to seattletimes.com,
‘If an earthquake occurs in the much closer Cascadia Subduction Zone, residents on the outer coast would have much less time to evacuate, perhaps just 10 to 20 minutes.  Tappero urged people to go to the Military Department’s website on emergency notifications — mil.wa.gov/alerts — to find out how to receive notifications and learn more about preparedness.’