A new geological record of the Yellowstone supervolcano's last catastrophic eruption is rewriting the story of what happened 630,000 years ago and how it affected Earth's climate. This eruption formed the vast Yellowstone caldera observed today, the second largest on Earth.

Two layers of volcanic ash bearing the unique chemical fingerprint of Yellowstone's most recent super-eruption have been found in seafloor sediments in the Santa Barbara Basin, off the coast of Southern California. These layers of ash, or tephra, are sandwiched among sediments that contain a remarkably detailed record of ocean and climate change. Together, both the ash and sediments reveal that the last eruption was not a single event, but two closely spaced eruptions that tapped the brakes on a natural global-warming trend that eventually led the planet out of a major ice age.

"We discovered here that there are two ash-forming super-eruptions 170 years apart and each cooled the ocean by about 3 degrees Celsius," said U.C. Santa Barbara geologist Jim Kennett, who will be presenting a poster about the work on Wednesday, 25 Oct., at the annual meeting of the Geological Society of America in Seattle. Attaining the resolution to detect the separate eruptions and their climate effects is due to several special conditions found in the Santa Barbara Basin, Kennett said.

One condition is the steady supply of sediment to the basin from land - about one millimeter per year. Then there is the highly productive ocean in the area, fed by upwelling nutrients from the deep ocean. This produced abundant tiny shells of foraminifera that sank to the seafloor where they were buried and preserved in the sediment. These shells contain temperature-dependent oxygen isotopes that reveal the sea surface temperatures in which they lived.

But none of this would be much use, said Kennett, if it not for the fact that oxygen levels at the seafloor in the basin are so low as to preclude burrowing marine animals that mix the sediments and degrade details of the climate record. As a result, Kennett and his colleagues can resolve the climate with decadal resolution.

By comparing the volcanic ash record with the foraminifera climate record, it's quite clear, he said, that both of these eruptions caused separate volcanic winters - which is when ash and volcanic sulfur dioxide emissions reduce that amount of sunlight reaching Earth's surface and cause temporary cooling. These cooling events occurred at an especially sensitive time when the global climate was warming out of an ice age and easily disrupted by such events.

Kennett and colleagues discovered that the onset of the global cooling events was abrupt and coincided precisely with the timing of the supervolcanic eruptions, the first such observation of its kind.

But each time, the cooling lasted longer than it should have, according to simple climate models, he said. "We see planetary cooling of sufficient magnitude and duration that there had to be other feedbacks involved." These feedbacks might include increased sunlight-reflecting sea ice and snow cover or a change in ocean circulation that would cool the planet for a longer time.

"It was a fickle, but fortunate time," Kennett said of the timing of the eruptions. "If these eruptions had happened during another climate state we may not have detected the climatic consequences because the cooling episodes would not have lasted so long."
Abstract:Santa Barbara Basin Sediment Record of Volcanic Winters Triggered by Two Yellowstone Supervolcano Eruptions at 639 ka

I find core sample results interesting.

Finding proof of a Yellowstone double eruption is interesting as that in geological terms of time, 170 years is like a single heartbeat.

Geologists suspect Yellowstone will erupt again in a series of eruptions that will culminate as a super eruption any time now.

The pattern of eruptions can be seen as a string of evidence that points to an eruption every 6-800,000 years.
Yet the most recent eruption consisted of rhyolitic lava flows that erupted approximately 70,000 years ago. The largest of these flows formed the Pitchstone Plateau in southwestern Yellowstone National Park.



The eruptions move as the continental plate moves over the hot spot creating a pattern of calderas. That evidence can be traced back in time.

When Yellowstone does erupt again, if a super eruption occurs it will be huge.



Yellowstone is not the biggest volcanic super eruption.
The biggest eruption (wiki) is
Guarapuava —Tamarana—Sarusas 132mya Paraná and Etendeka traps 8,600cukm volume Existence as a single volcano is controversial. Possibly a volcano chain.

By comparison Yellowstone's biggest eruption (18 eruptions above it) was
Yellowstone Caldera—Huckleberry Ridge Tuff 2.059mya Yellowstone hot spot 2,450cukm volume Largest Yellowstone eruption on record.

Source of graphics: http://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_sub_page_54.html

is that the one in russia that caused one of the biggest ELE's on earth? apperantly the lava hit a salt trap and killed like 98% of all life on earth?
http://en.wikipedia.org/wiki/Siberian_Traps

it says they both happened around the same time

Guarapuava is in the mid south of Paraná state in Brazil.

Tamarana is in the state of Paraná, Brazil.

The Paraná-Etendeka traps (or Paraná and Etendeka Plateau; or Paraná and Etendeka Province) comprise a large igneous province which includes both the main Paraná traps (in Paraná Basin, a South American geological basin) as well as the smaller severed portions of the flood basalts at the Etendeka traps (in northwest Namibia and southwest Angola).

The Permian–Triassic (P–Tr or P–T) extinction event, colloquially known as the Great Dying, the End-Permian Extinction or the Great Permian Extinction, occurred about 252 Ma (million years) ago, forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras.

Ref: wiki

Even tho Yellowstone is not the biggest volcanic eruption on record it is very big and potentially could be the biggest in recorded history. Tambora on certain scales is currently the biggest in recorded history but the cauldrea under Yellowstone currently has the capacity to be the biggest, if a super eruption occurs.

The 1815 eruption of Mount Tambora was one of the most powerful eruptions in recorded history, with a Volcanic Explosivity Index (VEI) of 7. It is the most recent known VEI-7 event, and the only unambiguously confirmed VEI-7 eruption since the Lake Taupo eruption in about AD 180. ~ wiki

No VEI-8 eruption has occurred in recent human history. The most recent such eruption is the Oruanui eruption that formed Lake Taupo, roughly 26,500 years before present. ~ wiki

Yellowstones last super eruption occured 630,000 years ago and while humans existed, they were not keeping records nor did they understand what was happening.



Example model output of possible ash distribution from a month-long Yellowstone supereruption. Results vary depending on wind and eruption conditions. Historical winds for January 2001 used here.

By comparrison



Map of the known ash-fall boundaries for major eruptions from Long Valley Caldera, Mount St. Helens and Yellowstone.
Source Page modified: 2016-01-08 09:32:52

Thus, the USGS historic ash cloud map has not been updated with the OP information taken from the core samples in the Pacific ocean.

Same graphic reference source: http://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_sub_page_91.html

Regardless of any projections, a super volcano at Yellowstone will devastate the continental United States and winds will globally affect the entire planet.

The historic frequency of Yellowstone is a 600,000 to 800,000 year cycle. The last super eruption occured 630,000 years ago. We are currently 30,000 years into the next eruption cycle.

Here is a 2017 image depicting Yellowstone's current magma chamber



Its huge!

Docu-drama Supervolcano film
(Decent movie if you ask me)
http://www.youtube.com/watch?v=1Cv9_AdB5Nw
Duration: 1:55:30

Might find this short video interesting
A Supervolcano Waking Up In The USA -6/8/2017
http://www.youtube.com/watch?v=go6tmmhE2N0

What If Yellowstone Erupted Tomorrow?
http://www.youtube.com/watch?v=YbHwPzYmRs4

interesting ... but why have I heard if yellow stones erupts ...
we are all goners ...

I watched a documentary on this. I only hope I'm already dust by then. Which will go first, or will it be simultaneously... ?

Yellowstone or the San Andreas fault causing California to become an island chain and Arizona being beach front property?

And I'm not trying to be funny.. it will happen

because no one knows for sure, since no one has ever seen it erupt... just dont be next to it when it does...

I have considered the same question.
When ya think about it, the Earth is on huge plates that are constantly moving. What affects one will certainly affect the others.



If you look at the plate movements depicted in the graphic from Bucknell, you can see the directional movement of the major plates.

The Atlantic mid-ocean ridge is forcing the North American plate north west. The Pacific plate is moving towards the subduction zone at the Marianas Trench at a different speed and angle.

The recent earthquake at the southern edge of the north American plate and the northern edge of the the Cocos and Caribbean plates (Mexico) has put pressure on the north American plate. That change has to be distributed someplace. It doesn't matter if the change is a separation or a collision. The earthquake set the plate in motion, that could cause a change in the San Andreas fault.

If the San Andreas has an earthquake it could send ripples of pressure change into the north American plate that could be just the right vibration to cause a Yellowstone eruption.

On the other hand, a Yellowstone Eruption could cause a change in the north American plate which might release pressure at the San Andreas fault causing a major earthquake.



- wiki

The map of north American Cratons gives a look at the underlying foundation of the plate which can isolate its structure and give possible pressure/vibration transference locals.

It is likely that the Mexico earthquake this summer will transfer to movement at the Keweenawan Rift which is near the Missouri Bootheel. Depending on the amount of movement there, the energy could transfer into the Wyoming archean causing a weakness at the Yellowstone hot spot.



If Yellowstone goes, it might cause a ripple effect on Mt Rainier, Mt St Helens and possibly Mt Adams or Hood. As Yellowstone empties the change in the plate pressures could cause instability in the nearby volcanic region. Any volcanic mountains near it could either erupt or have mudslides.

If you have ever broken ice in a pond and watched the movement of the sheets of ice it will give you an idea of the motion just like this. Put pressure on any given ice fragment and it affects the others near it.

So basically, if Yellowstone erupts and empties the resultant decrease of volumetric pressure on the plate will ripple out to all the edges of that plate, changed by the density of the basement formations.
The ripple effect will be different as it travels outward from the eruption.
Not only will you possibly be covered in ash (or lava), you might experience earthquakes or other events all around the plate as time passes.
It all takes time to manifest. Geological time scales are hard for humans to comprehend. It could be weeks, months or even years for it to happen but empirically, it must happen.

so with all the ripple effects it will effect the earth and bring people down with it ... I understand they don't really know and could happen anytime ... even we have learn that California can wash off the map been predicted... becouse of the hurricanes and floods ... I asked someone if they know this ...why not get out now ... they said some do not believe it will happen and where would all ...
those people go anyway ... I have lived there and I liked it ... except long way from my family ... the only thing I did not like ...

thanks for the tip

Tom, should we also consider the New Madrid fault into all this as well? I'm close to that one.

It's all scary when you think of it. Just pray I'm long gone before it does.

So Alaska probably wouldn't be a good choice for me to go do seasonal work for three or four months?

Only if you feel lucky...lol

Idk, it could years before anything happens, or it could be tomorrow..

Lol, it's a little cold anyways. Probably Arizona would be better.

It is a scary thought though.

don't let if's and might's ruin what you wanna do... yes, it's had a habit of erupting every 640,000 years or so, could be today or 10,000 years from now... plus, there's absolutely nothing anyone can do about it anyway...

That's why I mentioned the Missouri bootheel.

If you look at the north American plate, New Madrid is nearly in the center of the plate.
The plate is essentially twisting in motion as it moves.
New Madrid is affected by the twisting motion.
The plate locks at certain points around its edges and the twisting pressure is transmitted towards the weakest area (the center).
When a locked (stuck) point releases the motion is transmitted thru the plate and felt in the center as well.

Thing is, mightymoe is right.



Essentially, everything we think of as planet Earth is sitting on huge chunks of crust that is in motion floating on the asthenosphere which floats on the mantle. The lava pockets act like fluid against the lithosphere. There are weak spots melted by lava pockets which we see as volcanoes.
As the lithosphere moves around, hot spots move in relation to what we consider an static land mass but in reality it is the land mass that moves. It moves at such a slow rate we don't readily detect it. We know it moves because we look at the evidence of its history of movement.



In order for mankind to do anything about earthquakes or volcanoes we would need to be able to stop plate tectonics of all the Earth's lithospheres at the same time, then we would need to release the lava pocket pressures.

Its the movement of the plate that keeps Yellowstone from erupting more frequently. The hot spot doesn't have time on target to break thru as quickly. The issue is that the hot spot may be growing faster than the plate moves and the vibrations of fault action could weaken the plate to allow cracking where the hot spot pressure is high.

The only reason there is not a volcano at the New Madrid fault is because there is not a hot spot lava pocket close enough to the surface to cause a pressure dome.

That is true, thanks moe.

For what it's worth . . .

From the Pacific Northwest Seismic Center:

"The North American plate is moving to the west-southwest at about 2.3 cm (~ 1 inch) per year driven by the spreading center that created the Atlantic Ocean, the Mid Atlantic Ridge."

As the North American Plate moves over the Yellowstone hotspot, thicker and thicker crust ends up on top of the hotspot.

Thicker crust could make it more difficult for the Yellowstone hotspot to erupt.