Yellowstone volcano: What caused Yellowstone's violent eruptions? Will it erupt again?

Another eruption of the supervolcano beneath Yellowstone National Park could result in death and destruction on an unprecedented scale for much of the USA. Unimaginable amounts of ash would fall across thousands of miles across the States, destroying buildings, killing crops, and impacting key infrastructure. Fortunately the chance of another volcano eruption at Yellowstone occurring is unlikely, the United States Geological Survey (USGS) has confirmed.

Yellowstone’s supervolcano has experienced truly enormous eruptions in its long history.

One occurred 2.1 million years ago, another 1.3 million years ago, and the latest a relatively-recent 664,000 years ago.

There is little to indicate another super-eruption is due anytime soon – and it is even possible Yellowstone might never again erupt on a similar scale.

The USGS has today revealed how geologists understand the complex cause of Yellowstone’s eruptions all those times ago.

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What caused Yellowstone’s violent volcanic eruptions?

Volcanoes spew a mixture of gas, liquid magma, and crystals formed in the magma chamber.

The crystals mix with the ash deposited during explosive volcanic eruptions, and lava flows during less explosive ones.

The crystals in the deposits from both big and small eruptions in Yellowstone’s past have concentric zones.

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The information stored in these zones allows USGS scientists to reconstruct the “climate” in the magma chamber as the crystal grew, including changes in the temperature, pressure and chemistry in the period leading up to past eruptions.

The most recent zones reveal what was happening in the magma chamber immediately before an eruption.

Yellowstone’s magma system extends from the base of the Earth’s crust to the surface.

In the case either of an explosion or lava flow, several decades pass between the time the crystals first recorded the magma movement to an eruption.

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The USGS wrote: “If Yellowstone were to erupt again (which it may never do, mind you), it is possible that the eruption could be caused by a similar movement of magma from deeper in the crust to the shallowest magma chamber.

“This is something that would be easy to detect, as such a movement of magma would cause major earthquake swarms, significant ground deformation (far greater than the few inches per year of uplift or subsidence that are typical), and potentially even changes in gas or thermal emissions.

“These parameters are well monitored, so there will be ample warning of any potential future eruption.”

How big is the Yellowstone supervolcano?

The mantle rock feeding the mammoth Yellowstone supervolcano extends all the way to California and Oregon, it was recently announced.

Dr Victor Camp, a geologist from San Diego State University, revealed the mantle rock that sits beneath Yellowstone today may have originated from the core-mantle boundary sitting deep beneath San Diego.

Mantle plumes rise up because they are hotter and lower-density than the surrounding rock.

The plume feeding Yellowstone rose up and met the base of the North American tectonic plate, where it was blocked. At this point, the plume melted and started spreading west.

Dr Camp suggests that over the last two million years, the mantle rock that travels along these routes were responsible for eruptions at the Craters of the Moon lava flow field in Idaho.

These conduits end at the Medicine Lake volcano in California and Newberry Volcano in Oregon.

Dr Camp said last week: ”These channels have allowed low-density mantle to accumulate against the Cascades arc, thus providing a heated mantle source for mafic magmatism in the Newberry (Oregon) and Medicine Lake (California) volcanic fields.”

source: express.co.uk