A gigantic landslide shows the limit to how high mountains can grow | Hacker News Reader

A gigantic landslide shows the limit to how high mountains can grow

economist.com

118 pointsjesterpm79 comments

For comparison, this is between 4 and 5 times larger than the Osceola Mudflow (https://en.wikipedia.org/wiki/Osceola_Mudflow) that formed the 550km² of fertile plains around the south end of Puget Sound (near Seattle) and knocked a huge chunk out of Mount Rainier. If you drive from Auburn to Enumclaw, for example, notice how flat the land is and think about how that was hilly Cascade foothills and glaciated drumlins until 5500 years ago. The Osceola event was way bigger than Mt St Helens, and this one in the Himalayas was way bigger even that that.

Back-of-envelope, that Osceola event released about 10^19 Joules of energy*. The scale of these things is absolutely incredible.

According to my father, until around the time he was doing Geology at university (late 1960s), the consensus was that these kinds of events (and mass wasting more generally) were geologic processes that no longer happened (and hadn't really happened throughout the Holocene). I don't know the history in detail there, but it does seem true that only relatively recently we've had a real appreciation for how active Earth's geology still is.

* 4e15 cubic centimeters of material, 2 g per cc mix of rock and ice, mean elevation change 1000m

>that formed the 550km² of fertile plains around the south end of Puget Sound (near Seattle) and knocked a huge chunk out of Mount Rainier. If you drive from Auburn to Enumclaw, for example, notice how flat the land is and think about how that was hilly Cascade foothills and glaciated drumlins until 5500 years ago.

I grew up in this area... there are two tragedies that most people living in this area don't realize. One, before the war a good chunk of the region was populated by people of Japanese origin who farmed and never got their farms back after the war, and two, it is some of the richest farmland in the world - now covered with concrete tilt-up warehouses, highways, etc. Humanity is interesting.

Also grew up there. The soil was _very_ rich.

Related, there's a cool transition if you hike up the Greenwater river (starting at the town of Greenwater, heading towards FS70) there's a cool transition where the geology switches from Osceola mud to the more typical Cascade foothill geology (about half a mile from the White river).

its a real geologic zoo around there

It really is a zoo (and the whole of Western Washington is generally). If you're interested in the topic, I really enjoyed https://www.amazon.com/Roadside-Geology-Washington-Marli-Mil...

Love the geologic zoo!

I refer to botanical gardens as 'botanical zoos' as well

I believe zoo is short for "zoological garden," but of course it's taken on additional meanings. Still, one occasionally hears the term "zoological and botanical garden."

Wild to think about the fact that there were people living there who would have seen (or been buried) by that. Same with some of the cataclysmic floods and other events that came with the end of the last ice age.

> According to my father, until around the time he was doing Geology at university (late 1960s), the consensus was that these kinds of events (and mass wasting more generally) were geologic processes that no longer happened (and hadn't really happened throughout the Holocene). I don't know the history in detail there, but it does seem true that only relatively recently we've had a real appreciation for how active Earth's geology still is.

I can’t fathom how we could think that, surely as long as plates move around and stone weathers this sort of geological events can happen?

They’re certainly not common on historical timescales, so the odds you’d find yourself sharing time (let alone space) with one are low, but what would have made them stop?

Geology went hard for uniformitarianism during the 19th century as a reaction against the earlier "catastrophist" worldview, which had interpreted all major land forms as consequences of the great global flood described in the Bible (or something like it). This yielded a strong preference for theories involving continuous processes operating over long spans of time, and skepticism of theories involving sudden, violent changes. This swung back to a better balance during the 20th century; with the ghost of Noah's Ark exorcised, the role of local "catastrophes" in geologic history could again be taken seriously.

Wasn’t there some massive icedam caused lake that was the size of basically the entire Pacific Northwest and it flooded out in a matter of years? And nobody believed that could happen.

Right, figuring that out was an important step in our appreciation that catastrophes happen and are impactful on a large scale, you know, not just little things that get covered up by longer-term, consistent processes.

https://en.wikipedia.org/wiki/Glacial_Lake_Missoula

It's why western Washington state is all https://en.wikipedia.org/wiki/Channeled_scablands

The Mediterranean may also have been filled in a single event over a few months: https://en.wikipedia.org/wiki/Zanclean_flood

Plate techtonics was very new (and rather controversial, as I understand it), science in the late 1960s: https://en.wikipedia.org/wiki/Plate_tectonics#History_of_the...

My grandfather (a vulcanologist) set up measuring stations in Iceland in the 1930s to prove that Iceland was spreading apart. Unfortunately, the war interrupted that, and he died in the war.

Any more insights into his research and measurements that you know of? Thanks for sharing.

https://de.wikipedia.org/wiki/Ferdinand_Bernauer

"His greatest contributions to the academic world – proof of Continental Drift through his studies in Iceland and a crystal growing method now lost to mankind – attest to his considerable intellect and dedication."

https://expo.uw.edu/expo/apply/494/proceedings/show?id=68965

"Geschichtete Lava an islaendischen Vulkanen" von Ferdinand Bernauer, Berlin-Charlottenburg

Zietschrift der Deutschen Geologischen Gesellshaft Heft 2 Band 89 Berlin 1937 / Verlag von Ferdinand Enke in Stuttgart

>I can’t fathom how we could think that, surely as long as plates move around and stone weathers this sort of geological events can happen?

I learned recently (can't remember where, or how reliable) that plate tectonics did not create mountain ranges till carbon life had been around for awhile, because the carbon layers left behind are slippery (graphite) and allow one plate to slide over another plate. Prior to that, the plates simply pulverized each other.

anybody know if this is true?

They would mostly stop because now the Earth is nicely round. Most of the original bumpiness created during Earth's creation has been smoothed out. That's probably what he meant.

I've heard that the earth, if scaled down to the size of a pool/billiards ball, would be smoother than the ball.

I often use that to explain how spinning cue balls can manage to change the angle of the shot, given the same impact point as a non-spinning cue ball, in an effect pool players call "throw." [1]

The peaks and valleys of the pool ball will reliably grip like gears. Sometimes the balls even stick together momentarily before they release, changing the outcome of the shot, in another effect called "skid". [2]

Also the referenced site is an amazing deep-dive into a niche topic, worth a glance--especially the high speed videos demonstrating the physics of the game.

[1] https://billiards.colostate.edu/tutorial/throw/ [2] https://billiards.colostate.edu/resource_files/onoda_skid_ar...

"No, Earth is not as smooth as a billiard ball! ... The billiard-ball-sized Earth’s smoothness would be equivalent to that of 320-grit sandpaper."

https://ourplnt.com/earth-smooth-billiard-ball/

A comment on the article, though, says "I’d like to point out that Earth is about 3400 times flatter than a regulation pool table...I love saying it – The Earth is flatter than a pool table!"

> "Back-of-envelope, that Osceola event released about 10^19 Joules of energy*. The scale of these things is absolutely incredible."

I wonder can we put a kind of "earth turbine" to capture some of that energy? Maybe tap it somehow to not release all in one catastrophe and make it safer at the same time.

Before anyone gets excited, the landslide occurred in the 12th century or so :(

I was all excited to plan a rock hounding trip to the Himalayas. I even sent out the Sherpa bat signal (it’s a silhouette of me shaving a Himalayan yak), only to find out I’m eight hundred years too late.

I can’t say I am sympathetic about you having missed this Himalayan landslide. If you dawdled, it’s not my problem.

But if you’re willing to travel to the Alps, here’s one from a couple of weeks ago: https://www.theguardian.com/world/2023/jun/16/huge-landslide...

Given it happened well within recorded history I was excited to see if there were any contemporary accounts of the event, but disappointingly the article doesn't cite any, nor does it indicate whether there has been research on that facet. However remote in the Himalayas it may have been, surely such a cataclysmic landslide must have been felt and heard a significant distance away.

Smaller mountain landslides do occur in modern times. There was one here in Montana in 1959 that killed 27 people and blocked a major river. The effects are still visible today.

https://en.wikipedia.org/wiki/1959_Hebgen_Lake_earthquake

I mean the 'biggest' landslides are so big I'm not sure we'd fully be aware if one was going to happen soon.

https://en.wikipedia.org/wiki/Heart_Mountain_(Wyoming)

>Between 50 and 48 million years ago a sheet of rock about 500 square miles (1,300 square kilometers) in area detached from the plateau south of the Beartooths and slid tens of kilometers to the southeast and south into the Bighorn and Absaroka Basins

Luckily events like this are geologically rare. A bigger risk would be tsunamis from underwater mountain landslides.

the huascaran landslide too

> only to find out I’m eight hundred years too late.

and I thought I was bad for missing the timezone and being an hour late to watch the ESA's Euclid launch. Besides, I was able to watch mine in replay.

Some people like the idea of looking into the future, but I would prefer going back in time as a passenger only to see.. I mean we're time traveling any instant, just wait enough and you get to time travel, but there are some events like 100-200 years ago you can't ever really experience..

Apparently there are records of a loud noise being heard as far away as Timbuktu in the 12th century.

Now I want some yak momos.

https://archive.is/oO0dC

> As the rubble crashed down, the energy released would have been equivalent to around six times that of the Tsar Bomba

Interesting, wonder if this Approx 1190 event had a global impact.

https://en.wikipedia.org/wiki/Medieval_Warm_Period

Seems that ended in 1250, coincidence ??

> … the energy released would have been equivalent to around six times that of the Tsar Bomba

But how does that compare to an Olympic swimming pool full of double decker omnibuses being dropped from the same height?

The lengths people will go to to avoid using the metric system!

They go in increments of 50m. If you asked the width people go to, it would be 25m.

So your comment about avoiding the metric system is not really accurate. We don't say the Earth is approximately equal to 150 million kilometres from the Sun, we say one AU. We just use numbers that can be comprehended.

93 million miles you mean

No, I mean 3 million Olympic size swimming pools, you "do anything to avoid metric system" person

OK then about eight light minutes. Not sure there is any 31 mile long olympic swimming pool, though, but there are plenty of units out there so I can admit the possibility.

No, you mean 3 billion Olympic sized swimming pools.

oops, you're right. i forgot the units. i always forgot to normalize my units in school. at least i'm consistent which makes finding the bugs easy

Funny how we went through the monumental effort to build and adopt a whole new system of units just because a few people were bad at grade-school arithmetic and mental math.

It's especially weird because 12 is so much more useful than 10.

Oddly enough, it's still possible to have 12 metres or 12 tonnes within the metric system. I realise this is baffling and confusing to Americans but it's really true!

I think most people can understand what a meter is, or what a kilometer is, but would have no idea of what a kilojoule is, or what the energy inside a barrel of oil is.

I'm Canadian, and have never traveled to Europe but, every imported piece of food I've ever seen has the energy measured in kilojoules.

Actually it is both in kj and ccal

double-decker buses are clearly imperial units.

I think the Tsar Bomba was designed metric (unlike the contemporary US bombs and space program) so perhaps it was chosen for that reason?

Almost certainly, when you scale nuclear weapons to the energy of the atmosphere in general they become irrelevant.

The earth receives about 1.74x10^17 watts from the sun, continuously. On Tsar Bomba released a little over 200PJ, setting off one per day would be around 2.3x10^12 watts.

In other words to equal the energy from the sun you would need to detonate on the order of 1 MILLION Tsar Bombas per day.

Paper: https://doi.org/10.1038/s41586-023-06040-5

> Examining the surrounding cliffs for signs of a collapse, he noticed that a peak known as Annapurna IV offered a relatively smooth, steep face which seemed to fit.

I was interested in what the mountain looked like, and found a whole page dedicated to it [0]. In the picture of the west side you can see the steep face. The altitude map also has an unusually large flat area to the west of the mountain.

[0]: https://nepalhimalpeakprofile.org/annapurna-iv

My dad attended college in the 1950s. I liked reading his old textbooks.

The geology texts that predate plate tectonics are . . . interesting. They really didn't know where volcanoes and mountains came from.

What were the prevailing theories at the time?

Decent (shortish) summary here

https://en.wikipedia.org/wiki/Orogeny#History_of_the_concept

Oh man, it's been years. I'm visiting this weekend and I'll take a whirl through those old books.

Article didn't mention it but lightning is a significant force in mountain erosion too.

I don't think I have ever heard of this, have any more details?

There's water in the rocks. When it rains water gets trapped between rocks and layers of rock.

Then a storm comes in, more water, water is flowing filling cracks, pooling wherever it can, lightning strikes, the water trapped in and around some of the rocks very quickly heats up, turns to steam, and kaboom, you now have moving rock.

Presumably lightning strike erosion is a lot of energy over a short time compared to wind or water erosion which is much less energy but over much longer periods?

https://www.nationalgeographic.com/science/article/140105-li...

https://ui.adsabs.harvard.edu/abs/2016EGUGA..1815451H/abstra...

etc.

There are some high resolution nightside lighting storms from orbiting camera compilations on youtube that might impress just how much power zaps down in strikes.

I've been camping on a mountainside when a storm came over at night and rocky outcrops on the ridge above us were struck repeatedly by lightning.

In the morning, clear blue skies, and we climbed up to have a look. Was sadly not very dramatic, we were expecting chunks of rock blown off, but you could see that the sudden heat had created fresh fissures, and around what we thought was the ground zero of a strike, the surface of the rock had become friable for a few centimetres.

But water/ice is always going to be a dominant feature in rock wasting, those lightning cracks just give it easier ingress.

Unless their definition of "significant" is my definition of insignificant, it's not true.

The Sabche Cirque in question looks like a fascinating, and difficult place to explore. Check out narrow the exit drainage is!

https://www.researchgate.net/figure/Deep-and-narrow-gorge-of...

This Nasa blog post has a lot of good pictures of the immediate area that helps with understanding the shapes of the mountains there. I initially didn't realize just how choked down the drainage got. It seems like many cirques are described as having narrow exits but rarely are they this narrow.

https://earthobservatory.nasa.gov/blogs/fromthefield/2014/01...

Here's an earlier discussion related to this one: https://www.science.org/cms/asset/b7f5337c-0f34-4fb5-a907-61...

An ancestral mount Shasta in California collapsed sending a debris flow 28 miles covering something like 675sq km

Speaking of California, the Blackhawk Slide[1] in Southern California is pretty impressive. It occurred ~18,000 years ago and the landslide escarpment is still clearly visible today!

[1] https://blogs.agu.org/landslideblog/2019/11/15/the-blackhawk...

I think the title is off: the theoretical limit of how high a mountain can be on a rocky planet of given size can be found by physical considerations. The geological and other factors come into play, too to make the practical limit much smaller than the theoretical one.

I wonder if this is related (in a very large scale sense) to the sand pile model and self organized criticality...

https://en.wikipedia.org/wiki/Self-organized_criticality

The sand pile model: if one builds a pile of sand, dropping onto it a small number of grains at a time, individual grains will slide down the slope - but there's a critical angle at which any additional grains can trigger a catastrophic avalanche.

https://nautil.us/the-math-of-the-amazing-sandpile-238320/

If one builds a dry pile of sand.

A wet pile of sand has a different angle of repose. Between the lubrication and the rather substantial weight of the water, that's how most mudslides happen.

>In geology, unlike business, nothing is too big to fail.

Nothing is too big to fail in the business world either. Or at least nothing should be. If a business is that important to the economy but it can't keep itself afloat, something has gone horribly wrong on the business side, the government side, or both. Bailing out the business will probably not fix the underlying issues.

I am always amazed how thin the biosphere is - 3km down in the water , 3 up in the air - so roughly 1/1000 of the radius of the earth. And the vast majority of the biomass could probably be found in couple of hundred meters close to water level.

I seem to recall reading that there is actually more biomass below the surface of the earth than above, so you might be wrong on that one.

There is stuff living in rocks down to about 4km depth (the limiting factor is heat), including far below the seafloor. It's still an open question whether this biomass, some of which has been out of contact with the surface for hundreds of millions of years, exceeds the biomass of surface on Earth, but it's at least in the same ballpark.

It's kind of ambiguous how "alive" that biomass is as compared to life on the surface. If a bacterium reproduces every 10,000 years, how "alive" is it?

> Enough rock fell off a Himalayan peak to bury Paris to the height of the Eiffel Tower

> The falling mountain top would have displaced up to 27 cubic kilometres of rock—roughly enough to bury the entirety of Manhattan to about the height of the Empire State Building.

It's paywalled then on but I assume it's also enough rock to bury Dubai to the height of Burj Khalifa.

> It's paywalled then on but I assume it's also enough rock to bury Dubai to the height of Burj Khalifa.

Haha lol. These comparisons are always strange when I read them or see them in documentaries. "That's enough X to stretch all the way to the moon and back!"

In other words it's a lot. "No you don't understand! It's not just a lot! It's enough that if unraveled it could stretch around the Earth 10 times!!!"

Non-paywalled article:

https://arstechnica.com/science/2023/07/massive-peak-collaps...

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