The Orphan Tsunami of 1700 [pdf]
pubs.usgs.gov
The Orphan Tsunami of 1700 [pdf]
1–10 of 18 posts
Re: The Orphan Tsunami of 1700 [pdf]
#2Just learnt something from the article: It's interesting that the warping of the seafloor is what causes tsunamis, and not the shaking itself. It explains why a shoreline might sometimes recede away before a tsunami's crest strikes: The recession is caused by the seawater dropping with the seafloor, while the forward surge is caused by the ensuing bounce.
Re: The Orphan Tsunami of 1700 [pdf]
#3Cascadia has become a little bit of an obsession for me. I had my house retrofitted to help it withstand the inevitable next really big one that is coming because of what I have learned about it (I am also well above the tsunami flood zone). Subduction zones are crazy powerful but it looks like we are finally starting to learn important things about them. The challenge though is getting people to accept that they are real and will happen and entire cities need to move because of them (I'm looking at you Ocean Shores).
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?
Re: The Orphan Tsunami of 1700 [pdf]
#4Just learnt something from the article: It's interesting that the warping of the seafloor is what causes tsunamis, and not the shaking itself. It explains why a shoreline might sometimes recede away before a tsunami's crest strikes: The recession is caused by the seawater dropping with the seafloor, while the forward surge is caused by the ensuing bounce.
The largest tsunami on record came from a landslide in a bay: https://en.wikipedia.org/wiki/1958_Lituya_Bay_earthquake_and...
Re: The Orphan Tsunami of 1700 [pdf]
#5Just learnt something from the article: It's interesting that the warping of the seafloor is what causes tsunamis, and not the shaking itself. It explains why a shoreline might sometimes recede away before a tsunami's crest strikes: The recession is caused by the seawater dropping with the seafloor, while the forward surge is caused by the ensuing bounce.
The largest tsunami on record came from a landslide in a bay: https://en.wikipedia.org/wiki/1958_Lituya_Bay_earthquake_and...
Yeah that'll happen when a good chunk of a mountain basically drops into your body of water, lol:
"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
Re: The Orphan Tsunami of 1700 [pdf]
#6Cascadia has become a little bit of an obsession for me. I had my house retrofitted to help it withstand the inevitable next really big one that is coming because of what I have learned about it (I am also well above the tsunami flood zone). Subduction zones are crazy powerful but it looks like we are finally starting to learn important things about them. The challenge though is getting people to accept that they are…
Got any recs for contractors in the area to do the work?
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.
Re: The Orphan Tsunami of 1700 [pdf]
#7Cascadia has become a little bit of an obsession for me. I had my house retrofitted to help it withstand the inevitable next really big one that is coming because of what I have learned about it (I am also well above the tsunami flood zone). Subduction zones are crazy powerful but it looks like we are finally starting to learn important things about them. The challenge though is getting people to accept that they are…
Sea wall?
Re: The Orphan Tsunami of 1700 [pdf]
#8Cascadia has become a little bit of an obsession for me. I had my house retrofitted to help it withstand the inevitable next really big one that is coming because of what I have learned about it (I am also well above the tsunami flood zone). Subduction zones are crazy powerful but it looks like we are finally starting to learn important things about them. The challenge though is getting people to accept that they are…
Got any recs for contractors in the area to do the work? 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.
This was close to DYI with me and the local handyman figuring out a good way to tie my house to its foundation. Not a full retrofit but pretty good for my 100yo house with nothing remotely close to modern design. Here are some resources I found useful though.
https://dnr.wa.gov/sites/default/files/2025-03/ger_homeowner...
Re: The Orphan Tsunami of 1700 [pdf]
#9Cascadia has become a little bit of an obsession for me. I had my house retrofitted to help it withstand the inevitable next really big one that is coming because of what I have learned about it (I am also well above the tsunami flood zone). Subduction zones are crazy powerful but it looks like we are finally starting to learn important things about them. The challenge though is getting people to accept that they are…
Sea wall?
I'm not an expert by any means, but I think the issue with seawalls is they are built to stop waves, not something that acts more like the ocean getting deeper. The water a tsunami brings in is pretty different than a simple wave on the ocean.
Re: The Orphan Tsunami of 1700 [pdf]
#10Just learnt something from the article: It's interesting that the warping of the seafloor is what causes tsunamis, and not the shaking itself. It explains why a shoreline might sometimes recede away before a tsunami's crest strikes: The recession is caused by the seawater dropping with the seafloor, while the forward surge is caused by the ensuing bounce.
Dropping or rising. At the borders of the sea and land plates the sea plates are slipping slowly below the continental crust. Pieces of the land crust get caught and dragged down. Over long periods of time you'll see forested land get dragged down below sea level and flooded to die.
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.