The Orphan Tsunami of 1700 [pdf]
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The USGS has published a comprehensive report on the Orphan Tsunami of 1700, a massive tsunami that occurred in the Pacific Northwest without a known earthquake epicenter, sparking discussion among HN users about its historical and scientific significance.
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"The large mass of rock, acting as a monolith (thus resembling high-angle asteroid impact), struck with great force the sediments at bottom of Gilbert Inlet at the head of the bay. The impact created a large crater and displaced and folded recent and Tertiary deposits and sedimentary layers to an unknown depth."
With updated modeling showing that impact triggering the glacier to lift and subsequently release even more material, it's shocking anyone in the bay survived at all.
Edit - found a video with said papers modeling implemented, pretty neat: https://www.youtube.com/watch?v=B1axr5YGRwQ
"The wave definitely started in Gilbert Inlet, just before the end of the quake. It was not a wave at first. It was like an explosion, or a glacier sluff. The wave came out of the lower part, and looked like the smallest part of the whole thing. The wave did not go up 1,800 feet, the water splashed there."
Still insane, but it was the immediate splash that scoured away trees and soil cover up to 527 meters up the mountain face, not a proper tsunami.
Both the fisherman and his son survived btw.
The a rupture will occur, and in the biggest earthquakes you can get a fault that can rise 20 meters almost instantly causing trillions of tons of ocean to suddenly have to go somewhere. After the quake and tsunami you'll see the flooded forests can be many meters above land were new forest will grow and slowly start sinking again.
Side note, any actual geologists in the room? The recent Philippians 7.6 looks like it may be following a growing pattern of megathrust forshocks to my -deeply- untrained eye. Does someone with actual knowledge and training have a take on that?
What should I get done? (ranch 2 story built in 90s). Cost to expect? Been having bad luck lately with bids and sketch contractors. Takes a lot of effort to sift through.
https://dnr.wa.gov/sites/default/files/2025-03/ger_homeowner...
https://www.wabo.org/earthquake-home-retrofit
Another reply here alludes to the fundamental problem with tsunamis by mentioning a phenomenon that's more like the ocean suddenly growing deeper. That's not exactly right but it is close in a way. Tsunamis are vast water displacement events and completely unlike normal large tidal or wind-caused (storm surge) waves because while you might have a storm wave of, say, 15 meters height and a tsunami of the same height, the The tidal/storm wave has much less run-up mass/volume, it's usually just a bit more than what you get right before your eyes. The tsunami on the other hand has a lateral run-up mass behind it that stretches back for as many as dozens of kilometers if I remember correctly, and all of that mass has to keep moving forward until it exhausts itself. Thus when the wave first hits, that's just the very beginning of all the destructive power it brings. A whole vast freight train (so to speak) of surging water mass, with all the displacement energy that caused it built right in, still has to keep moving forward until it expires. This vastly destructive process can take a while to complete itself.
You see why this is also a problem when it comes to sea walls too? If you have a 15 meter concrete sea wall and it gets hit by a 20 meter storm wave, the wave might sort of cross over its top and flood a bit on the other side, but otherwise the sea wall does its basic job. But if that same sea wall is struck by a tsunami of even slightly less than its height, the surging lateral mass of water behind the initial wave just keep pushing forward tremendously until it heavily overflows the wall.
If you watch videos of the 2011 tsunami, and especially videos where the wave actually hits barriers and then overflows them completely, you'll see the above effects in action. Terrifying stuff and very unique to tsunamis, which, I repeat, are completely unlike any ordinary large wave.
https://www.newyorker.com/magazine/2015/07/20/the-really-big...