How a melting glacier led to a 500-meter-high tsunami
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That would be just a few months after the Blatten landslide. There was another major landslide in the Alps a few years ago that I can't recall the name of, and IIRC at the time global warming was suspected in that one as well.
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Marmolada glacier sérac collapse, perhaps? That one was massive enough to get wide coverage worldwide. 2022 or so, over 10 victims. Mind you, that's nothing compared to the landslides and GLOF events that occur more and more frequently in the Himalayas…
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I believe Ars covered this similar event recently as well:
https://www.usgs.gov/publications/a-rockslide-generated-tsunami-a-greenland-fjord-rang-earth-9-days
https://www.usgs.gov/publications/a-rockslide-generated-tsunami-a-greenland-fjord-rang-earth-9-days
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So Alaska has now had at least two mega tsunami's in the last 80 years. I believe the 1958 Lituya bay tsunami was the first time we learned about rockslide tsunamis. And in the aftermath they started looking for evidence of previous events and found a bunch of shorelines in bays in Alaska with evidence of tremendous damage running hundreds of meters up from the water with new growth trees along the shore and older trees above the damaged areas.
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Has a tsunami of this height ever been photographed or filmed? All I have in my head are hollywood depictions
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Well, interesting. My partner just booked us on a cruise to there. It’s ok though. I’m sure it will be fine 
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A huge chunk already fell, and then everything else that was weak got raked over by the seiche wave, so it’s probably the safest it’ll be for a while.Well, interesting. My partner just booked us on a cruise to there. It’s ok though. I’m sure it will be fine
As long as your cruise only takes you to just that fjord, anyway.
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It presumably would have looked like a lot of fog and a deafening roar, then the GoPro is suddenly under water and you can’t see anything, then a seal eats it and everything goes dark for the rest of the footage.
Although, with over 400m height the wave might actually poke above the fog.
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Suprised the Valdez 1964 video did not get mentioned. Link:
View: https://www.youtube.com/watch?v=1bv2GGjcfCY
View: https://www.youtube.com/watch?v=1bv2GGjcfCY
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In 2020 this warning was issued about another nearby escarpment that could collapse.
https://dggs.alaska.gov/hazards/download/Barry_Arm_Landslide_Working_Group_2020_05_14.pdf
https://dggs.alaska.gov/hazards/download/Barry_Arm_Landslide_Working_Group_2020_05_14.pdf
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SittinPlushW/aRoyalFlush
Smack-Fu Master, in training
70 m/s = 156 mph
481 m = 1578 ft
Edit: wasn't intended as U.S.-centric mindset of "wahhhh, i don't understand MKS units, why didn't you convert in for me", but rather to express the stunning massiveness (in terms of my daily life). Thought that just putting up the numbers was enough to show my jaw-drop disbelief (and I was in a hurry). Was gonna post my initial estimates as "I can't even imagine ~170mph & ~1600ft", but went for accuracy via a quick search. Annnnd, yes please, I would love it we converted to MKS [heads to changeDOTorg to start a petition #goodLuckWithThat]
481 m = 1578 ft
Edit: wasn't intended as U.S.-centric mindset of "wahhhh, i don't understand MKS units, why didn't you convert in for me", but rather to express the stunning massiveness (in terms of my daily life). Thought that just putting up the numbers was enough to show my jaw-drop disbelief (and I was in a hurry). Was gonna post my initial estimates as "I can't even imagine ~170mph & ~1600ft", but went for accuracy via a quick search. Annnnd, yes please, I would love it we converted to MKS [heads to changeDOTorg to start a petition #goodLuckWithThat]
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“Hopefully this kind of data ends up on desks of policymakers and regulators...."
:-/
:-/
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In the current political climate you’d get a LEGO film made by AI showing the event.
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Frustration over not being able to visualize what a 500m wall of water looks like. Something so mind numbingly massive and rare taking place just last year (not 100,000 years ago) I kind wish someone would find a well preserved trail cam on a beach in Japan.
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Pretty much like a 500m mountainside, I guess, but fast-moving and wet (although I doubt you'd experience much of the "wet" if it hit you).
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And that was not even 50 meters -- around a tenth the size of the event in the article.
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The Lituya bay event killed one boats crew but actually had survivors in two other boats.
Evidence of ocean crossing megatsunami exist in Aus presumably from the collapse of the cone of the volcano on Molokai.
Evidence of ocean crossing megatsunami exist in Aus presumably from the collapse of the cone of the volcano on Molokai.
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I think you might be getting down-voted because you didn't say...
70 m/s = 252 kph
481 m = 481 m
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Meh, just a megathrust earthquake. Only a 27 foot tsunami. Granted it was one of the largest megathrust earthquakes ever recorded.
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Probably because that was caused by an earthquake that triggered a landslide, it was underwater, instead of above it and other damage resulted from the earthquake. It also wasn't caused by climate change, but geological movement.
This one wasn't an earthquake that did it. It was just a landslide caused by the reduction of the supporting mechanisms that kept that chunk of rock from falling. Yes, it registered on seismographs, but so will someone jumping up and down near one - it wasn't tectonic. It was directly attributed to melting glaciers. AKA Climate Change.
So, while there are similarities in the mechanics that created the waves, the differences are pretty stark in why those different mechanics happened in the first place. I'd guess this wasn't mentioned because, while earthquakes are often causes for tidal waves, even these kinds, this was wholly attributed to climate change, and is a threat that, unlike tsunamis in the ocean, can happen anywhere there's water, an overhang, and that overhanging piece of a mountain being held up by melting glaciers.
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Hard to visualize this event at scale. I remembered a video that the YouTube channel Destination Adventure posted last year showing a collapse of part of the salmon glacier that he had caught on his drone. It's about 13 minutes long. Amazing footage.
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Geologists have known about them for some time. But the 1958 even was one of the first that happened with witnesses. And then in 1963 came the Vajont Dam disaster, and that really put rockslide megatsunamis on the map.
And it is worth noting that Lituya Bay was triggered by a strike-slip earthquake, where Vajont and this event were created by a change in the local forces holding the rock in place, no seismic trigger needed. (The earthquakes they recorded were symptoms, not causer.)
We do have some before-and-after images of similar events. For example, here's one of Lituya Bay; all that bare rock is where the tsunami cleaned house.
These have also been observed (repeatedly) at Paatuut, Greenland, Karrat Fjord, Greenland, Stromboli, Sicily, Aysén Fjord, Chile, and scores of other places. If you have studied geology or world affairs, this event isn't a surprise.
Here you go:
And here's an oblique view showing the trimline where all the vegetation was stripped by the tsunami:
Please remember that (1) these microseisms were on the order of -1M to -4M; had you been standing on the rock right over them, you probably wouldn't have noticed them, and (2) in order to determine which chunk was about to fall, we'd need a much denser net of seismometers in the bay than we have.
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The tsunami at issue in Valdez was around 40-50m. Not directly sparked by the earthquake; rather it was sparked by a landslide that the earthquake triggered.
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There is a Norwegian movie about a similar event:
https://en.wikipedia.org/wiki/The_Wave_(2015_film)
(Note the year, there is at least one other movie with the same name.) I think I saw it on Netflix, but several years ago, it isn't there now. It was very well done.
https://en.wikipedia.org/wiki/The_Wave_(2015_film)
(Note the year, there is at least one other movie with the same name.) I think I saw it on Netflix, but several years ago, it isn't there now. It was very well done.
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I think of it this way. The water would have reached the top floor of this building. (The Lotte World Tower in South Korea)
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Not really. It wasn’t a 500-meter wave. It was a wave that reached 500 meters up a slope in the terrain.
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If I had been anywhere near the rock fall with camera, I would be scrambling up to high ground while soiling my underwear. It would have been very scary barely believable.
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Google images/videos of Nazare. Those are often 25-30m and they already stretch my imagination. (And yes, people surf there.)
View: https://www.youtube.com/watch?v=QBVt8pzjnL8
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"The metric system is the tool of the devil! My car gets forty rods to the hogshead and that's the way I likes it." --Abe Simpson
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Well, hopefully it doesn't end up on the desks of the current crop of American policymakers and regulators, because their only response will be to say, "What the hell? Why isn't this defunded yet?!"
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