Posted on 01/27/2021 8:26:36 AM PST by BenLurkin
The last huge earthquake, the last really “Big One” to hit the Pacific Northwest Coast, struck around 9 p.m. on Jan. 26, 1700 — 321 years ago.
Called Cascadia, the magnitude 9.0 quake caused the entire Pacific Northwest coastline to suddenly drop 3 to 6 feet and sent a 33-foot high tsunami across the ocean to Japan.
The last huge earthquake, the last really “Big One” to hit the Pacific Northwest Coast, struck around 9 p.m. on Jan. 26, 1700 — 321 years ago.
Called Cascadia, the magnitude 9.0 quake caused the entire Pacific Northwest coastline to suddenly drop 3 to 6 feet and sent a 33-foot high tsunami across the ocean to Japan.
“Japanese sources document this earthquake, which is the earliest documented historical event in Western Washington. Other evidence includes drowned groves of red cedars and Sitka spruces in the Pacific Northwest. Indian legends corroborate the cataclysmic occurrence,” according to HistoryLink.
The earthquake ruptured what is known as the Cascadia subduction zone from British Columbia to northern California — the area of overlap between two of the tectonic plates that make up the earth’s surface, the Juan de Fuca plate and the North American plate.
(Excerpt) Read more at seattletimes.com ...
I thought they were on Martha’s Vineyard.
Just read it. Fascinating! scary.
FEMA thinks five minutes for the shake, and eighteen minutes from the P-wave until landfall, to bring the wash cycle into play. The survivors will have best results if they can make it to I-5. Any solid leads about earthquake spurred volcanic activity?
I looked it up. The article said not to worry about it.
Interesting. Article I read said geologists said not to worry about it.
Does anybody remember the Great Tohoku quake in Japan in 2011? That was exactly the kind of subduction zone that the Cascadia is. And yes, that one hit 9.0. If the Cascadia lets go, and does what they call a ‘full 9 rip’, it will affect everything from Vancouver BC all the way down to northern California.
I was in Western Washington for the Nisqually quake in 2001. A 6.8 is scary enough. I don’t ever want to live through a 9.0.
The Lord of Facebook owns 700 acres there, though.
Thanks for this fascinating bit of quake history.
I hope this piece of history never repeats itself!
I guess you live in Kansas.
This topic was posted , thanks BenLurkin.
They have estimated the Cascadia quake lasted about 5 minutes. But yeah - you’re not going to be able to move very well with all that shaking going on!
I think I’m prepared for it (live near Seattle), but probably not as well as I think that I am!
I see others had already commented about the 5 minutes or more. Sorry!
A large earthquake on the Cascadia Fault zone has happened 13 times in the last 6000 years. We are probably overdue for the next one.
The New Yorker article is a scary one. Very well written. Is probably written on the scarier side to bring attention to the issues. The gal that wrote the article got a lot of push back and emails, etc. from public officials, etc.
IIRC, she said that in Seattle, west of interstate I-5 would be trashed.
Some official said that she was wrong and being a scare-monger that everything west of I5 would be destroyed.
She replied something like “I said it would be trashed, not destroyed. But from the official estimates there would be 70% of the people without water (or sewer), 60% without electricity, 80% of the bridges into Seattle would be non-drivable - and these conditions would last for a minimum of 6 weeks. That sounds like “trashed” to me.”
I know I’m off on the numbers, but it was something like that. I might be optimistic on the 6 weeks.
Seattle used to have emergency mutual aid with Portland and Vancouver, B.C. After discovery of the Cascadia Fault Zone the cities are partnered with cities to the east. The I-5 corridor will be non-drivable.
For Seattle, supplies will be flown into Moses Lake 150 miles to the east. Huge airport for testing airplanes. Then loaded on to trucks to a staging area near the pass on I-90. Then loaded onto helicopters and flown 40(?) miles to Seattle.
It is going to take a long time to even get a bottle of water to somebody stuck in Seattle.
>>Move away from cliffs
At level 9, you could find yourself standing “on a cliff” in an instant!
>>“When it hits, Where will you be?”
The eternal question
The Great Atomic Power - The Louvin Brothers
https://www.youtube.com/watch?v=AojCqHwsbX0
Yes, my wife and I have been here for every quake that has happened in Western Washington for the past 60 years. The Nisqually quake lasted long enough that my wife and I both walked to a doorway and stood under it on the third floor of our house. Neither of us felt panicked by it.
In 1965 my family had time to walk out of the house before it stopped.
I didn't realize that any place was “brought to its knees” around here by the Nisqually quake. But looking it up I see now that it is claimed that $2 Billion in damage was caused. I know that many old buildings were required to be retrofitted with earthquake mitigation construction devices at great expense. And it was also used as an excuse to tear down and build billions of dollar in new schools none of which suffered much if any damage that I am aware of. Many single story wooden schools were torn down here in the name of earthquake safety.
I do believe that we are overdue for a much larger earthquake that really will pancake a lot of places.
We had a friend who was a firefighter in Anchorage during the devastating 1964 earthquake there. That truly was a disaster. Fortunately Anchorage was a much smaller place back then and people there were far more self-reliant during that time period.
https://www.theatlantic.com/photo/2014/05/1964-alaskas-good-friday-earthquake/100746/
I can see how “the Big One” would demolish everything west of I-5.
I’m so glad that my daughter, who lived in Seattle for twenty years, has returned home to Pennsylvania. Our earthquakes register at 2-3 on the scale.
“Burbank hills for the Northridge quake”
That must have been an E-ticket ride. I was in north OC for both Sylmar and Northridge and those were scary as hell 50 miles away. “Only” 6.6 and 6.7 quakes
Sylmar tossed all of the water out of a swimming pool in the Fullerton hills, taking shards of sliding glass door through the entire house.
It was a rude awakening. Living in LA you get used to the rolling type. This was sharp and violent, like a train derailment. The first aftershock seemed just as bad. I couldn’t believe that apartment building survived with just a few cracks in the walls.
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