Stay Eat Events Weather Beaches

Oregon Coast Science: Why No Tsunami with the Alaska Earthquake?

Published 01/23/2018 at 7:45 PM PDT - Updated 01/23/2018 at 10:45 PM PDT
By Oregon Coast Beach Connection staff

Oregon Coast Science: Why No Tsunami with the Alaska Quake?

(Oregon Coast) – Early Tuesday morning saw something startling for Oregon coast residents: a tsunami watch issued because of a 7.9 earthquake off the Alaskan coast. After two or so tense hours, filled with some locals heading inland anyway, the watch was lifted and those who weren't still sleeping through it could rest easily.

Meanwhile, in Alaska things were not so laidback. Tsunami alert sirens went off in many parts of Alaska and even British Columbia, waking residents and calling for evacuations to higher ground. Those warnings were finally lifted too. However, a six-inch tsunami wave was recorded coming into one section of Alaska beach.

It all hearkened back to the great quake of 1964, which killed over 100 in Alaska and caused a tsunami wave that inundated Seaside, killed four children on a beach in Newport and washed out the bridge at Cannon Beach (which in turn caused the creation of the now famed Cannon Beach Sandcastle Festival).

Not that anyone wanted this, but why no tsunami with this quake?

Latest Coastal Lodging News Alerts
In Seaside:
Includes exclusive listings; heatwave availability
In Cannon Beach:
Who's got rooms open for the heatwave this weekend
In Manzanita, Wheeler, Rockaway Beach:
Room openings this weekend
In Pacific City, Oceanside:
Who has rooms for this weekend hot weather inland
In Lincoln City:
Openings for this weekend to get away from the heat
In Depoe Bay, Gleneden Beach:
Where rooms are to be found this heavy traffic weekend
In Newport:
Room openings, get away from the heatwave
In Waldport
New amenities offered, find openings for the week
In Yachats, Florence
Availability for this weekend; lodgings not listed anywhere else

The USGS and geologists on the Oregon coast – including Seaside's Tom Horning – have the answer.

Unlike that quake in '64, or the big one expected off the Oregon coast someday, this was a kind of underwater earthquake that simply does not displace much water. This was a strike-slip fault, meaning the two chunks of landmass slide against each other horizontally instead of vertically.

The big nasty coming to this coastline is part of a fault system that will cause a subduction quake – where two plates pop against each other suddenly in an up and down direction, instead of side to side. It's also known as a thrust quake, according to scientists.

This one was side to side – of the strike-slip variety.

Where to stay in this area - Where to eat - Maps and Virtual Tours

“Usually, little vertical displacement takes place, so there isn't a tsunami,” Horning said.

Still, Horning said, these kinds of quakes are capable of creating tsunami chaos. If a submarine strike-slip rattler causes massive underwater landslides, shaking up debris from the continental shelf, then tsunamis can occur. This was just the situation from another Alaska-centered shaker in 1946 that caused extensive damage in Hawaii.

If this sort of quake were to occur on land – as it does with the San Andreas fault in California – it can bend train tracks and tear fences apart.

In a subduction zone, like that off the Oregon coast, it is the result of one continental plate shoving itself underneath another. When that tension releases, one plate drastically moves up or down. This will cause substantial movement of ocean water, resulting in a tsunami.

It takes a 7.0 magnitude quake to generate a tsunami. Small quakes around magnitude 2 to 3.5 occur about 20 times a year off the Oregon coast.

Oregon Coast Lodging

 






More About Oregon Coast hotels, lodging.....

More About Oregon Coast Restaurants, Dining.....

 

Oregon Coast event or adventure you can't miss

 



Coastal Spotlight


LATEST Related Oregon Coast Articles

Razor Clamming N. Oregon Coast Closed Until Sept 30
Razor clamming will close on almost all Clatsop County beaches starting July 15. Seaside, Gearhart, Warrenton
Is Newport's Yaquina Head an Old Oregon Coast Volcano? (Video)
The history of geologic discoveries is almost as fiery as the origins. Science
Seaside Beach Discovery Days Again Brings Amazement to N. Oregon Coast
Interactive activities that lend a whole new layer to your coastal experience. Seaside events. Seaside Aquarium, science
Find Oregon Coast Lodging Availability for Heatwave, July
Most lodgings, hotels, motels and vacation rentals will be filled up
Invasive Species Find Points to Disturbing 'Garbage Bridge' to Oregon Coast
Fears of invasive species coming over on what is being termed a garbage bridge. Science, Hatfield
N. Oregon Coast Nature Hike Events Around Manzanita Provide Breathtaking Sights
Both are relatively easy hikes and involve some amazing views and glimpses of wildlife. Manzanita events
Secrets and Fun Facts of Depoe Bay: Video of Oregon Coast Wonders
Some intriguing fun facts you need to know: whales, natural features, hidden spots. Travel tips, kids
N. Oregon Coast: Seaside Beach Wheelchairs, Drone Video Raises Money
Seaside now has beach wheelchairs and northern Tillamook County has more money for historical sites

Back to Oregon Coast

Contact Advertise on BeachConnection.net
All Content, unless otherwise attributed, copyright BeachConnection.net Unauthorized use or publication is not permitted

Oregon Coast Lodging
Rentals
Specials

Dining

Events Calendar

Oregon Coast Weather

Travel News

Search for Oregon Coast Subjects, Articles

Virtual Tours, Maps
Deep Details