‘System is very active’ Why Yellowstone volcano is rocked by thousands of earthquakes
Yellowstone Volcano: Super eruptions 'are very rare' says expert
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Anywhere between 1,500 and 2,500 earthquakes are detected in the Yellowstone region each year, making it one of the most seismically active parts of the US. Located in the Western United States, the Yellowstone volcano caldera covers about 30 by 45 miles within the 3,500-square-mile Yellowstone National Park. The volcano has witnessed three monstrous eruptions in the past – roughly 640,000, 1.3 million and 2.1 million years ago – and many people believe it could blow again one day.
To put the eruptions into perspective, the US Geological Survey (USGS) estimates volcanic debris belched from Yellowstone blanketed much of the Western US “third of a meter deep several hundred kilometres from Yellowstone”.
A more recent period of volcanic activity went off about 70,000 years ago when the volcano oozed enough lava to form a geological feature known as the Pitchstone Plateau.
Yellowstone park sits atop of a volcanic system that, although mostly solid, still fuels the parks hot springs and geysers.
Yellowstone’s subsurface is also marked by numerous fault lines that contribute to the region’s frequent earthquakes.
A USGS scientist in charge of overseeing the Yellowstone Volcano Observatory (YVO) has explained how these features combine to trigger thousands of earthquakes across the park each year – and why you
Michael Poland, the present Scientist-in-Charge of the YVO, spoke to AccuWeather’s Adam Del Rosso about the world-famous supervolcano.
The interview touched upon recent reports 43 earthquakes were detected in the Yellowstone region last month – a report which sparked fears an eruption is brewing deep underground.
One Twitter user said: “Apparently there were 43+ earthquake/tremors last month at Yellowstone, but they are currently waiting for signs of a volcanic eruption stating that mother nature gives warning signs before an eruption.
Yellowstone volcano: Expert debunks theory of 'overdue' eruption
“Sorry boys but Pompeii should be a prime example of no volcanic warning signs.”
According to Dr Poland, however, 43 earthquakes are well below the par for Yellowstone and are not an indicator of a brewing cataclysm.
He said: “The Yellowstone system is really active as a tectonic system, so we see anywhere in the neighbourhood of about 1,500 to 2,500 earthquakes per year on average.
“So typically there’s 100 to 200 earthquakes every month at Yellowstone and these are mostly caused by very small faults that are mostly caused by very small faults.”
The resulting earthquakes are minor – typically in the magnitude 1 to 2 range.
Between four and five tremors each year are stronger than that at magnitude 3.
Dr Poland added: “But the very small events caused by all of the water that’s moving around the subsurface and the area is chockfull of faults, because it’s in a very tectonically active part of the Western US, and it’s also weak because of the heat that’s being input to the system by the Yellowstone volcanic system.
“So that combination of the weak crust due to the heat, and all the faults, and all the water moving around the subsurface just creates the perfect conditions for lots and lots of smaller earthquakes.”
Despite what you might have heard on social media, Yellowstone is not going to erupt any time soon and there is no evidence to suggest the volcano is overdue for another eruption.
According to the USGS, the volcano could pop one day. But the odds of this happening within our lifetime are extremely slim.
And the volcano would give off many warning signs before blowing its lid.
The USGS said: “YVO has not detected signs of activity that suggest an eruption is imminent.”
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