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The Geology Thread (Earthquakes, Volcanoes, Paleohistory, Asteroids)

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The Geology Thread (Earthquakes, Volcanoes, Paleohistory, Asteroids)

#1

Post by Lakigigar »

My vision

The most dangerous volcanoes that are capable of very large eruptions are during our lifetime (VEI 7+)
Laguna del Maule (Chile)
Iwo-Jima (Japan)
Okataina (New Zealand)
Serdan-Oriental (Mexico)

There are others that are also dangerous, but they're not likely to erupt (Long Valley, Yellowstone, Toba, Taupo) or too small (like Katla, Sakurajima, Rainier, Agung, Ilopango, ...) while having regardless very dangerous circumstances in certain situations (near populated areas). A volcanic eruption doesn't have to be very powerful to kill or bring disruption.
The island of Iwo Jima is about twenty metres higher than it was in 1945 due to a growing magma chamber underneath. The beach where the American forces landed in 1945 is now 17 meters above the ocean surface. The island has been pushed up by 1 meter every 4 years since several hundred years. It is only a matter of time before the whole island explodes. Although few people live on Iwo Jima itself, a large eruption would cause a tsunami that could devastate southern Japan and coastal China including Shanghai and Hong Kong. The team estimates that in Japan the tsunami could be 25 meters high. The eruption of the similar sized Kuwae volcano in Vanatua in 1458 caused a tsunami 30 meters high in northern New Zealand, and lead to the cultural collapse of Polynesia.
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#2

Post by Lakigigar »

In terms of volcanoes, it has been very quiet so far in the 21st century. We only had 1 VEI 5 eruption since 1991 (in Chile in 2011), though 1991 had a VEI 5 and a VEI 6 eruption (Pinatubo and Hudson). We had 10 VEI 5 and 3 VEI 6 eruptions in the 20th century. We had at least 7 VEI 5 eruptions, 2 VEI 6 eruptions and 1 VEI 7 eruption. But the further back you go, the more eruptions that might have been missed. For one of those VEI 6 eruptions, we haven't been able to find the source.

In terms of earthquakes, compared to the 20th century, the early 21st century has been very active. We had 10 M8.5+ earthquakes through the entire 20th century. We've had 6 between 2004 and 2012 (four of them being in Indonesia).

Between 1964 and 2004 there wasn't a single recorded M8.5+ earthquake, and in the 8 years following that, we've had 6 of them. Indonesia probably had to slip. The Sendai one has a periodicity of 1100 years, and the latest one before 2011 was somewhere around 869. Of course there are other segments that slip too in Japan, but that one had to slip first.

It's hard to know where the next severe one will be, but it's possible we won't have another M9+ in our lives. Lisbon, Cascadia are all not for soon. Less sure about Japan, Indonesia and Chile, but I remember not having noticed something that was about to slip, but I could easily misread or miss something. Indonesia is geologically extremely active, so it's very frequent there and always a threat, because it's very long (same for Chile which is also very long).

I'm not sure if the faultline near Canada, Mexico, NW-Southern America, or California is, is capable of megathrusts. The faultline near Seattle in Washington is capable of megathrust quakes every 400+ years, the latest one was in early 18th century, the next one is likely to happen in the 22th century, because it's very periodic in terms of intervals. In Greece, Italy & Turkey, there might be someting capable too of M8.5 quakes. Right now, it's found the faultline south of Crete is capable every 2000 years (or more). The latest one was in 365. More uncertainty, but I don't think it's there yet. I'm not sure about northern Chile. It had one 150 years, but it seems to happen quite frequently. We however had a recent M8.2 one in 2014. I'm not sure if that was the one. Not sure about Eastern Russia (Kamchatka) and Nepal too. I think New Zealand has megathrust fault zones, and it hasn't slipped for a long time. I believe that's a very dangerous one. There are some in the western Pacific that might be dangerous too (near Pacific Islands or Philippines, but not sure)

The real danger are the M7 / M8 ones that can still cause a lot of misery and deaths... .
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#3

Post by 3eyes »

I read today that Etna has been doing its thing for awhile but not really bothering anybody.

One theory about the mass extinction (90 % of all species) at the end of the Permian is that there was massive volcano activity somewhere in Siberia that went on for years and created a sort of nuclear winter. I guess if Yellowstone were to blow it could be the same sort of thing.

Laki, I hope I'm not repeating myself but I majored in geology in college -- the discovery of the Mid-Atlantic ridge happened my senior year, so pretty much all I learned was Wrong, Wrong, Wrong, Also my great-great uncle, G K Gilbert, was chief of the USGS and more or less invented geomorphology. He discerned that the pocks on the moon and Mars were impact craters rather than volcanoes and has craters named for him on both.

These days I try to keep up with discoveries in Precambrian paleontology, which in the 50s was pretty much terra incognita - stomatolites were called "cryptozoa" and that was about the extent of it.
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#4

Post by maxwelldeux »

That is fascinating... I do have a weirdly strong interesting in geology. That's cool shit.
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#5

Post by Lakigigar »

3eyes wrote: February 27th, 2021, 12:03 am I read today that Etna has been doing its thing for awhile but not really bothering anybody.

One theory about the mass extinction (90 % of all species) at the end of the Permian is that there was massive volcano activity somewhere in Siberia that went on for years and created a sort of nuclear winter. I guess if Yellowstone were to blow it could be the same sort of thing.

Laki, I hope I'm not repeating myself but I majored in geology in college -- the discovery of the Mid-Atlantic ridge happened my senior year, so pretty much all I learned was Wrong, Wrong, Wrong, Also my great-great uncle, G K Gilbert, was chief of the USGS and more or less invented geomorphology. He discerned that the pocks on the moon and Mars were impact craters rather than volcanoes and has craters named for him on both.

These days I try to keep up with discoveries in Precambrian paleontology, which in the 50s was pretty much terra incognita - stomatolites were called "cryptozoa" and that was about the extent of it.
Not really. Yellowstone and the Siberian Traps are different mechanisms. It's more likely temperature went sharply up in an already boiling climate. Yellowstone could possibly evolve into an even more dangerous volcano if it moves under the N-A craton which it will do between now and 2 million years, but it's more likely the hotspot will have no activity for 50 million years because the tougher rock will be hard to penetrate. There's little (to none) volcanic activity under cratons, but Siberia's activity 250 million years ago, was under a craton. Siberia's activity was mostly effusive, but with lots of explosive and toxic gases. Yellowstone is more extremely explosive. But the characteristics of the volcano & hotspot will likely soon change.

The hotspot that was under Siberia 250 million years is very likely the same one as the one under Iceland (since we can see track the scars of the Iceland hotspot, as well track the movement 250 million years ago. And what happens if you go 250 million years back in time, Siberia is on top of it. The scars also point toward it being under Siberia around 200 to 250 million years ago.
About a third of the basaltic lavas erupted in recorded history have been produced by Icelandic eruptions. Notable eruptions have included that of Eldgjá, a fissure of Katla, in 934 (the world's largest basaltic eruption ever witnessed), Laki in 1783 (the world's second largest)
Even today, it still produces large basaltic eruptions. If you multiply Laki with 1 million you get the Siberian traps, since Laki was unusual for a basaltic eruptions for it being effusive but with explosive gases & contents.
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#6

Post by Lakigigar »

A few tens of millions of years ago it was a part of the North American plate that slid over the Hotspot, and as that broke apart magma pushed through and created Greenland. As the now archipelago of Greenland slid away it lost its capacity to have eruptions pretty permanently.

Before that it was Newfoundland that popped up as it slid over the hotspot. And before that we had the same hotspot creating the largest Large Igneous Province on the planet, the North Arctic Igneous Province (NAIP). Before that Labrador and Baffin Island slid over the NAIP, and that put us at about 95 million years ago. And 130 million years ago it created the Alpha Ridge. Any super volcano will have an inferiority complex to that eruption.

Before that and even further down in time it was known as the Siberian Traps, the largest on land eruption. And now we are back 250 million years in time. Before that things get a bit harder to track.
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#7

Post by Lakigigar »

https://en.wikipedia.org/wiki/Paleocene ... al_Maximum

I suspect this climate change event is also linked to the Iceland hotspot and Greenland volcanism. This climate change event is considered to be a modern precursor of modern climate change. The problem is lots of it's evidence will be found under the Greenland icecap.
The associated period of massive carbon release into the atmosphere has been estimated to have lasted from 20,000 to 50,000 years. The entire warm period lasted for about 200,000 years. Global temperatures increased by 5–8 °C.[1]

The onset of the Paleocene–Eocene Thermal Maximum has been linked to volcanism and uplift associated with the North Atlantic Igneous Province, causing extreme changes in Earth's carbon cycle and a significant temperature rise.
Since at least 1997, the Paleocene–Eocene Thermal Maximum has been investigated in geoscience as an analog to understand the effects of global warming and of massive carbon inputs to the ocean and atmosphere, including ocean acidification.[8] Humans today emit about 10 Gt of carbon (about 37 Gt CO2e) per year, and will have released a comparable amount in about 1,000 years at that rate. A main difference is that during the Paleocene–Eocene Thermal Maximum, the planet was ice-free, as the Drake passage had not yet opened and the Central American Seaway had not yet closed.[9] Although the PETM is now commonly held to be a "case study" for global warming and massive carbon emission,[1][10] the cause, details, and overall significance of the event remain uncertain.
You have people saying climate change is of all times, and yeah sure they're right, but it's the rate and speed of it that is unprecenteded. Last time, something comparable happened was +-55 million years ago, and our rate is still 20 to 50 times higher than during that period.
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#8

Post by Lakigigar »

Also volcanoes can produce a "nuclear winter". That type of volcanism is more common, since that require more explosive events. Yellowstone is more of that type. Toba which erupted around 72.000BC, possibly caused the bottleneck theory, lack of genetic diversity in humans because we were near extinction. Now, that one is one of the most explosive and most gigantic eruptions ever found. It's likely to be the biggest eruption in the last 25 million years (but something might've unnoticed or lost it's evidence or part of it over time).

The latest Yellowstone eruption more than 600.000 years ago produced 1000 km3 of dense rock materials
The Lava Creek Tuff is distributed in a radial pattern around the caldera and is formed of 1,000 km3 (240 cu mi) of ignimbrites.
The latest Toba eruption produced 5300 km3 of dense rock materials, more than 5 times more. The nuclear winter lasted for more than a century, at one point causing a drop of 15-20°C in global temperatures. After a century it returned to a drop of 1°C according to a study i've read.

Observations and analysis contradict it. They argue the winter was less severe, but that recovery took much longer or possibly didn't even happen, severing the Ice Age. It's now associated with a 1000 year cooling episode. (which is possibly because simulations don't take other things in effect like a cooling episode strenghtening itself because of the change it caused itself, like effect of albedo on a climate with a feedback that strengthens cooling or strengthens melting)

Just to say, the climate is less stable than people think, and much more complex and complicated. It's dangerous to mess around with, because of the existence of numerous invisible tipping points
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#9

Post by 3eyes »

This is all very interesting, Laki. (Having read up on Laki in Wikipedia I now know where your handle comes from.) You've obviously delved into this deeply.
Where are all the quotes from?

I also read that the only time the sea level has been lower than now since the beginning of the Paleozoic was at the Permian/Triassic boundary (Permian glaciation?).
Comments?

Yes, all those tipping points. Try to fix one thing and you create more problems. We could just nuke Panama and that would get rid of the Gulf Stream and eveything would be back to some Pliocene normal.

It sometimes helps to take the long view. :P
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#10

Post by Lakigigar »

3eyes wrote: February 27th, 2021, 6:26 pm This is all very interesting, Laki. (Having read up on Laki in Wikipedia I now know where your handle comes from.) You've obviously delved into this deeply.
Where are all the quotes from?

I also read that the only time the sea level has been lower than now since the beginning of the Paleozoic was at the Permian/Triassic boundary (Permian glaciation?).
Comments?

Yes, all those tipping points. Try to fix one thing and you create more problems. We could just nuke Panama and that would get rid of the Gulf Stream and eveything would be back to some Pliocene normal.

It sometimes helps to take the long view. :P
Source?

In older literature, i've indeed seen people state the Permian was a period of glaciation. In other literature they usually define that period as most of the Carbonifirous and Early Permian, but i've indeed seen very contradicting takes on the climate of the Permian, ranging from coldest to warmest era. That being said, Carboniferous was mostly wet and cold, until the Carboniferous rainforest collapse (and swamps too), which stimulated the evolution from amphibians to reptiles and indicates a drier climate (which is likely due to the formation of a supercontinent Pangeae. Insects didn't become very large anymore, indicating lower O² levels, while the Early Triassic was very hot and very dry.

Perhaps the Permian saw the gradual transition to a rough continental climate (like Siberia in northern and southern Pangeae and like the Sahara / Death Valley in the middle, while coasts were battered by extreme hurricanes due to superoceans. Perhaps it was both very hot with some minor glaciation? The only (bigger) microcontinent not attached to Pangeae was Southern China and some said life on land survived only there during The Great Dying, because it's likely to be one of the few regions with rich ecosystems (less harsh climate) and also to be less affected by massive volcanism (because it was not on the same continent), though 260 million years ago the smaller Emeishan traps occured which was in modern SW China and i'm not sure where that is (Pangeae or that island)

End of Carboniferous

Image

Late Permian

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Equatorial rainforest disappeared as deserts spread across central Pangea. Though the southern ice sheets were gone, an ice cap covered the North Pole. Rinforests covered South China as it crossed the Equator.
Image

Early Triassic
The interior of Pangea was hot and dry during the Triassic. Warm Temperate climates extended to the Poles. This may have been one of the hottest times in Earth history. Rapid Global Warming at the very end of the Permian may have created a super - "Hot House" world that caused the great Permo-Triassic extinction. 99% of all life on Earth perished during the Permo-Triassic extinction
Yes, all those tipping points. Try to fix one thing and you create more problems. We could just nuke Panama and that would get rid of the Gulf Stream and eveything would be back to some Pliocene normal.
Not so sure, since when the America's collided, is exactly the point where Quaternary glaciation started, which makes sense, because Pacific sea currents would continue into the Atlantic bringing more "moderation".
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#11

Post by Lakigigar »

images don't work, but you can find everything here for who loves prehistoric maps or climate maps

http://www.scotese.com/earth.htm

http://www.scotese.com/climate.htm

Image

Image

both suggest colddf early permian, warmer late permian but possibly still with minor glaciation
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#12

Post by Lakigigar »

So, i believe the southern parts evolved from a permanent ice cap to a Siberian climate (warm summers, very cold winters esp. for southeast) because Gondwana moved north + supercontinent dynamics, while the north might've some minor glaciation episodes similar to Greenland but more Siberian (because Pangeae as a whole also moved north). S. China was tropical, battered by hurricanes, while most of Pangeae had a very continental and very dry climate similar to the Atacama desert in terms of how the desert might've looked like, with the extent of the Sahara, probably much bigger since most of Europe, all of North America, most of Southern America and 3/4th of Africa was desert, apart from smaller and more periodic short-term climate variations.

Sahara nowadays is mostly quite a new desert, which is why the sand is so beautiful, because it goes through cycles of short lush savanna and long extreme desert periods, influenced by Milankovich cycles and ice age dynamics. The desertification of the Sahara (mostly center, east & Middle East), caused humans to migrate towards the Nile, Euphrates and Tigris. Livestock grazing might've sped up the desertification, but it also gave birth to civilization and agriculture, since humans permanently settled around those rivers, because of the changing climate.

I think this is the most accurate answer I can give based on what I know and all sources i've read.
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#13

Post by Lakigigar »

Lakigigar wrote: February 24th, 2021, 3:00 pm My vision

The most dangerous volcanoes that are capable of very large eruptions are during our lifetime (VEI 7+)
Laguna del Maule (Chile)
Iwo-Jima (Japan)
Okataina (New Zealand)
Serdan-Oriental (Mexico)

There are others that are also dangerous, but they're not likely to erupt (Long Valley, Yellowstone, Toba, Taupo) or too small (like Katla, Sakurajima, Rainier, Agung, Ilopango, ...) while having regardless very dangerous circumstances in certain situations (near populated areas). A volcanic eruption doesn't have to be very powerful to kill or bring disruption.
The island of Iwo Jima is about twenty metres higher than it was in 1945 due to a growing magma chamber underneath. The beach where the American forces landed in 1945 is now 17 meters above the ocean surface. The island has been pushed up by 1 meter every 4 years since several hundred years. It is only a matter of time before the whole island explodes. Although few people live on Iwo Jima itself, a large eruption would cause a tsunami that could devastate southern Japan and coastal China including Shanghai and Hong Kong. The team estimates that in Japan the tsunami could be 25 meters high. The eruption of the similar sized Kuwae volcano in Vanatua in 1458 caused a tsunami 30 meters high in northern New Zealand, and lead to the cultural collapse of Polynesia.
https://watchers.news/2021/02/23/laguna ... um=twitter

This one is already raised. I even didn't saw it... they raised the alert. To me, this is right now the dangerous volcano over the world, based on the potential of erupting.
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#14

Post by Lakigigar »

Also, a volcano erupted in iceland, 30 km's (15 miles) away of the capital Reykjavik. There were a few ticking time bombs in Iceland, this wasn't one of them though, so to me it was a surprise.

Image

For some reason, from above, it looks like a horse, lol.
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#15

Post by 3eyes »

From the latest issue of Science:

https://www.sciencemag.org/news/2021/03 ... ater-world

Btw, you asked about my source awhile back - Ron Redfern, Origins (2001). Not exactly the latest, I guess, but it's a marvelous tome which is now too heavy for me to lift. Focus on plate tectonics, movement of continents thru geological time.

It's astounding that the isthmus of Panama was closed off in the Tertiary, without which we wouldn't have a Gulf Stream (let's hope we can keep it).

A propos of which, I just found this: https://www.tamug.edu/newsroom/2016arti ... anama.html
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#17

Post by Armoreska »

Lots of volcanoes going off recently
he or A. or Armo or any

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#18

Post by Lakigigar »

Image

Image

Image

Image

ash and SO² cloud (our sunsets might look weird)

Image

boom whole island covered
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#19

Post by Lakigigar »

apparently this could be the worst volcanic eruption since Mount Pinatubo in 1991 based on recent observations by volcanoexperts...

Weird sunsets and slight global cooling can at this rate be expected.
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#20

Post by Lakigigar »

Armoreska wrote: April 11th, 2021, 4:41 pm Lots of volcanoes going off recently
Some swarm also now on Katla.. if she erupts, we will know it for sure (but she does that sometimes, those swarms)

Yes this is kind of getting an active year so far.

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#21

Post by Lakigigar »

Grimsvotn might also go this year (or perhaps 6 to 12 months). It's almost there to erupting too. But i don't think it'll be as explosive as that one in 2011. In the 20th century however Grimsvotn was way less active than in the 21st century so far. The 2011 eruption was similar to the 1873 eruption, and before that only the Laki fires were worse.

Image
Grímsvötn has a southwest-northeast-trending fissure system, and the massive climate-impacting Laki fissure eruption of 1783-1784 was a part of the same fissure system. Grímsvötn was erupting at the same time as Laki during 1783, but continued to erupt until 1785. Because most of the volcano lies underneath Vatnajökull, most of its eruptions have been subglacial.
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#22

Post by joachimt »

Semi on-topic: I watched San Andreas last night. Had a nice time.
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#23

Post by Lakigigar »



A video about la soufrière. Almost certainly a VEI 4 eruption. It's the largest volcanic eruption in at least 250 years in the Caribbean.
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#24

Post by Lakigigar »

My calculations suggest around 6th largest eruption of the 21st century (could be a bit lower though, as not everything is completely trustable, although the 0.3 cu km of La Soufriere might be an underestimation too. So definitely one of the larger ones, but not one that eclipses the other ones, so it happens around regularly at least between 1.5 and 4-5 years, although La Soufrière's eruption was possibly the largest since 2011 (3 larger ones happened in 2011), so we were a bit overdue in terms of statistics, while 2011 was volcanically an unusually active year.
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#25

Post by Lakigigar »

Made this post on a different forum, wanted to repost it here too (made other posts too, but i wanted to share this one

Image

Just to put things in perspective, especially given we recently saw a study suggest that it even erupted around 5500 cu km of volcanic material (almost double the size of it, and almost three times that of Yellowstone's largest eruption) 75.000 years ago.

There is no strong evidence of cooling, but it likely might explain the bottleneck theory in that humans actually show little DNA variation, suggesting that around 1000 humans survived this disaster. In ice cores, there's no strong evidence of very strong cooling, there is some evidence but not strongly, you would think there was more cooling. The effects weren't as severe as models suggest, however much more prolonged which could be explained by 1. ice cores going so far not accurately showing temperature variation by decade but more by thousands of years 2. the volcano cooling the climate so much that it triggered feedback mechanisms like advancing glaciers, increasing albedo effects so that there was no point of return possible.

There is however a vegetation model that suggests that most of the Northern Hemisphere vegetation by that point simply was dead, and never grew back in it's original form until the major ice age was over. Temperatures in ice cores suggest that the climate never returned to pre-Toba levels, so while the climate was already cooling, it probably increased the speed of cooling for a bit, and was a trigger to a more colder climate and for the strengthening of the major Ice Age. It also coincides with the disappearance of an African Humid Period which usually happens in interglacials, but also confirms the disappearance of vegetation observed in models.

That being said, volcanoes are not the cause of changing the climate, it's part of the climate cycle. It's not like volcanoes were never been around, and life still exists. It's find a way to adapt. Especially given the current distribution of continents is there for a long time as well as plate tectonics, it probably happens quite regularly on a geological scale, even eruptions of that size.

(You can make a case of less volcanic activity in supercontinent phases, but the most massive basalt flood eruptions happened around than, and that actually makes sense, since more magma gets trapped in the mantle when less volcano erupts regularly, which might explain those basalt floods, as well as the breaking up of a supercontinent again, and the formation of new tectonic fault lines and perhaps hot spots), again suggesting a cyclus in that (as well as explanation for it).
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