Super volcanoes and asteroid/comet impacts

[Monsterboy]

I want to know whether the effect of an asteroid/comet strike in the vicinity of a currently dormant super-volcano can increase or decrease the likelihood of eruption in the future.

Where exactly should the asteroid/comet hit to depressurise the magma chamber and delay a super eruption and where should it hit to set it off in the near future (if possible) ?

 

[jedishrfu]

I don't think these are easy things to predict. They are heavily dependent of the geometry of the supervolcano and where its containment is stronger or weaker. Of course, any impact would cause the system's equilibrium to change and that could mean an eruption. If the pressure was sufficiently low as in it recently erupted then a direct impact could further relieve the pressure.

How did you imagine this to play out?

 

[Monsterboy]

Well then, forget about supervolcanoes, I want a 10 km across asteroid to hit the Earth and cause maximum damage to the human civilization, where should it hit ?

Should it hit the Middle East, will the oil fields and/or natural gas reservoirs become unusable and catch fire that can never be put off ? causing an additional shortage of fuel to the world economy (which is overdependent on oil) on top of the other damages that impact will cause ?

Or, should it crash head-on in the Atlantic ocean and damage the US, Africa and Western Europe ?

Details about where to hit and the angle of decent will be helpful.

 

[Bystander]

I want a 10 km across asteroid to hit the Earth and cause maximum damage to the human civilization, where should it hit ?

It wouldn't make a whole/hole lot of difference ("That's a joke, son," said Foghorn Leghorn). https://en.wikipedia.org/wiki/Chicxulub_crater

 

[BWV]

Forget supervolcanos, they are nothing compared to flood basalts, and there is some thought that the real killing mechanism behind the Chicxulub strike was that it triggered the Deccan traps on the other side of the world

http://www.d.umn.edu/~mille066/Teaching/2312/Elements%20Articles/Jones%20Elements'05%20LIPs.pdf

 

[nuuskur]

if a ~10km across piece of rock slams into the planet at super sonic speeds, you needn't worry whether it fulfils your damage expectation

 

[Nik_2213]

Taking the opposite approach, there's no evidence that a comet or asteroid impact from Scholz's Star's pass ~70,000 years ago was responsible for Toba's mega-eruption.
https://en.wikipedia.org/wiki/Scholz's_Star

whimsical:
Is Jupiter's Red Spot evidence of a mega-impact ??
/

FWIW, that pass will have stirred our Oort Cloud but, given the long in-fall time, any such objects have yet to arrive...

 

[BWV]

Taking the opposite approach, there's no evidence that a comet or asteroid impact from Scholz's Star's pass ~70,000 years ago was responsible for Toba's mega-eruption.
https://en.wikipedia.org/wiki/Scholz's_Star

whimsical:
Is Jupiter's Red Spot evidence of a mega-impact ??
/

FWIW, that pass will have stirred our Oort Cloud but, given the long in-fall time, any such objects have yet to arrive...

Have not seen anyone tying supervolcano eruptions to impacts, but there is thought that may be related to flood basalts, which are may more destructive than supervolcanoes like Toba

https://en.m.wikipedia.org/wiki/Siberian_Traps

One of the major questions is whether the Siberian Traps were directly responsible for the Permian–Triassic mass extinction event that occurred 250 million years ago,[8] or if they were themselves caused by some other, larger event, such as an asteroid impact. A recent hypothesis put forward is that the volcanism triggered the growth of Methanosarcina, a microbe that then spewed enormous amounts of methane into Earth's atmosphere.[9] Ultimately altering the Earth's carbon cycle based on observations such as a significant increase of inorganic carbon reservoirs in marine environments.[9

 

[DrStupid]

Forget supervolcanos, they are nothing compared to flood basalts, and there is some thought that the real killing mechanism behind the Chicxulub strike was that it triggered the Deccan traps on the other side of the world

In addition to the activation of the Réunion hotspot it also released huge amounts of sulfate aerosoles (because the impact site is rich in sulfate) which may cause the strongest possible impact winter. Yes, the Chicxulu impact seems to be the worst possible scenario. It could only be exceeded by a direct hit into a nuclear reprocessing unit.

 

[stefan r]

...

Details about where to hit and the angle of decent will be helpful.

Here is a model that varies by angle. They say you get maximum rock vapor at a 30 degree angle. Rock vapor in the atmosphere causes climate chaos. A 30 to 45 degree angle should send a shower of ejected meteors raining down hundreds of kilometers away. Animals in the shower are baked well done and plants burn.

I suspect you could hit a coastline and shower the continent with flaming meteors and also send a tsunami in the reverse direction.

...
Should it hit the Middle East, will the oil fields and/or natural gas reservoirs become unusable and catch fire that can never be put off ? causing an additional shortage of fuel to the world economy (which is overdependent on oil) on top of the other damages that impact will cause ?...

The oil fields are trivial in this case. Limestone is converted to calcium oxide in cement manufacturing at much lower temperatures. Earth's atmosphere has around 10¹⁴ kg of CO₂. Your 10km comet could pack more than 10¹⁴ kg of CO₂ itself. If it hits limestone a few kilometers deep then you could add the same order of magnitude quantity of CO₂ . The flaming meteors will burn vast areas of forest. The dust cloud blocking the Sun will cause a global plant and plankton die off. Plants hold 5 x 10¹⁴ kg of carbon and soil 15 x 10¹⁴kg.

The Saudi oil fields are in sandstone. Sandstone and shale has much less carbon than limestone/chalk.

Well then, forget about supervolcanoes, I want a 10 km across asteroid to hit the Earth and cause maximum damage to the human civilization, where should it hit ?
...

Or, should it crash head-on in the Atlantic ocean and damage the US, Africa and Western Europe ?

You could go for both a tusnami and maximum carbon emission by hitting an island. Abaco island in the Bahamas could still shower the East Coast with debris. Many islands in the pacific are coral based.

Instead of hitting limestone you could aim for a gypsum mining area. Vaporizing calcium sulfate and ejecting it into the stratosphere should shower Earth in acid rain. Sulfer dioxide itself is an anti-greenhouse gas. In the short run sulfuric acid cools climate. Dust also blocks sunlight so you should be able to set off a nuclear winter. The cold snap will help kill the plants. Sulfur reduces the atmosphere's ability to remove greenhouse gasses so in the long term it increases warming trends. There should be extra methane released by decaying plants. Much of the sulfur dioxide will fly over the ozone layer so should cause depletion. I have not seen any study of what lime, CaO would do to the ozone layer.
Crashing the comet near Fort Dodge Iowa you would get the sulfur, carbon/carbonate, and it would burn a lot of North America. You lose the tsunami but melting glaciers and expanding oceans should flood most European coastal cities anyway. An Atlantic tsunami would leave the Philippines and Tokyo dry. Water vapor has a short term warming capability that offsets the short term cooling from dust. Hitting the gypsum beds would whiplash the ecosystem going from a short extreme cooling to long term extreme warming.

You could consider hitting a salt deposit. The salt could kill the plants and most of the soil organisms in the fallout zone. So if the nuclear winter is not intense enough you still get adequate die off for extreme climate change.

It might be worth considering the effect of a comet containing a lot of nickel dust. Large amounts of nickle can cause cancer, liver failure and skin lesions in humans. Nickel powder is lethal to fish and algae in small quantities. Metallic asteroid dust could also have a fair amount of lead, arsenic, uranium or other heavy metals.[/QUOTE]

 

[Nik_2213]

Slightly tangential...
If Big ELE hit the Moon instead, and we 'only' caught the secondary stuff, that's the scenario for the tale I've posted in the short-story thread at top of forum...

 

[Monsterboy]

If a large asteroid or comet breaks-up above the earth, is it possible for the pieces to hit multiple locations separated by thousands of kilometers ?
Say, for example three pieces hitting the North Atlantic, Western Europe and Siberia respectively. Would that require a very odd angle of decent if at all possible ?

 

[Nik_2213]

Uh, yes, provided the break-up was sufficiently prior to impact. 'Shoemaker-Levy' was disrupted by Jovian pass, the fragments dispersed along orbit before taking their famous 'Big Dive' at next encounter.

Also, many objects seem to be 'binary' or 'quasi-binary'. Either an accompanying 'mini-me' or, like 'Ultima Thule', a 'contact binary'. Plus any mix there-of.

FWIW, digging the terrestrial impact lists should find several cases where a large crater and significant smaller crater appeared at the same time, within the errors of determination. Short of finding 'smoking guns' of their mixed ejecta, we must remain wary...

( Sorry, reply a bit terse as one cat is chasing cursor across my displays, Boss Cat keeps emptying my 'pending' tray onto floor, and third of four is helping me type... )

 

[stefan r]

If a large asteroid or comet breaks-up above the earth, is it possible for the pieces to hit multiple locations separated by thousands of kilometers ?
Say, for example three pieces hitting the North Atlantic, Western Europe and Siberia respectively. Would that require a very odd angle of decent if at all possible ?

Print a polar projection map. Throw darts at it. The darts could hit The North Atlantic, Germany, and Siberia. You could even hit Mongolia and Kansas too. The Kansas impact would be at a very high angle. A meteor coming from North could enter the atmosphere above Ecuador and Indonesia. A projection map centered on Finland instead of the North Pole would make impacts in your spread more likely and would make them closer to vertical.

If you concoct a scenario where the breakup occurs and the pieces are separated by 12 hours you could have impacts on opposite sides of Earth.

A binary asteroid orbiting the Sun in a polar orbit could hit the arctic on one pass and then hit the antarctic 6 months later. The odds of that are quite low.

There are claims that a number of meteors found came from 4-vesta. These would have flown around for a few million years before hitting Earth and can be found anywhere on Earth. Whether all HED meteors really came from 4-vesta is debated. It is certainly possible.

Every meteor shower event is ascribed to a former comet. For example the Perseid meteor shower last a month and has a peak over a few days. All of the meteors belong to Swift-Tuttle. Anyone who can see Perseus (all of northern hemisphere and tropics) is in direct line of the shower.

 

[Nik_2213]

Slightly off-topic but, IMHO, this is relevant...
https://phys.org/news/2019-03-million-year-old-deathbed-linked-dinosaur-killing-meteor.html

 

[essenmein]

According to the wiki on the chicxulub impact:

"Excavated material along with pieces of the impactor, ejected out of the atmosphere by the blast, would have been heated to incandescence upon re-entry, broiling the Earth's surface and possibly igniting wildfires; meanwhile, colossal shock waves would have triggered global earthquakes and volcanic eruptions."

Sounds pretty devastating, regardless of where it hits!

Another interesting one is the Manicouagan Reservoir (Eye of Quebec), which is hypothesized to be part of a multi impact similar to shoemaker-levi.