The Yellowstone caldera in northwest Wyoming is a geologically active site of a recent supervolcano.
In the previous three episodes, I discussed the movement of the yellowstone hotspot, the
chain of calderas it left, the three most recent caldera forming eruptions from this hotspot, and
the volcanic activity which occurred after the Lava Creek eruption 640,000 years ago. This
video will state the odds of a future eruption and answer the question that is most frequently asked,
"is yellowstone about to erupt?" When someone asks this question,
they are typically referring to the possibility of a future supervolcanic eruption. Despite what
a certain tabloid that ends in .co.uk keeps ridiculously suggesting, the chance of such
an eruption occurring in the next several thousand years are essentially zero. The odds of a caldera
forming eruption each year from Yellowstone are 1 in 730,000. However, there is more. If
a caldera forming eruption was to occur right now, it wouldn't actually be that big. Let me explain.
You may have read about Yellowstone's vast magma chamber or magma reservoir. For example, In 2015,
a reputable study found that the magma reservoir had a volume of 46,000 cubic kilometers. However,
a magma reservoir and a magma chamber are not the same thing. A magma chamber is the body of
partially molten rock which can reach the surface through an eruption. A magma reservoir is a much
deeper feature that feeds a magma chamber. So, the important thing to look at here is the magma
chamber, which in the case of yellowstone, has a volume of 4,000 cubic kilometers.
However, the vast majority of this volume is solid rock. Only about 7% of the area is
molten rock. As a result, if every bit of molten rock in the chamber was to erupt today, it would
produce less than 280 cubic kilometers of lava. This would still be a very large eruption, but
would not be considered a supervolcanic eruption. A much more likely type of future eruption would
not create a caldera, but rather erupt lava onto the surface through a rhyolite rich lava flow.
Since the Lava Falls eruption 640,000 years ago, 80 of these eruptions have occurred. However,
the most recent of these occurred slightly more than 70,000 years ago. As a result,
even this type of eruption is unlikely, with the odds of 1 in 25000 each year.
A type of eruption which is almost certain to occur in the next several thousand years
is a phreatic eruption. Phreatic eruptions do not erupt any lava, but are the equivalent of
putting a water bottle above a fire. Eventually, the heat will cause the water to flash to steam
and cause an explosion. 4 such eruptions, which are also termed hydrothermal explosions
have occurred in the last 10,000 years within yellowstone. This type of eruption is essentially
impossible to predict with current technology, but even the odds of this are quite low. The chance
of a large phreatic eruption, which creates a 100 meter or larger wide crater is 1 in 700 each year.
So, what would happen before a future magma producing volcanic eruption?
Before a volcanic eruption from yellowstone, you would notice two things. You would first notice
increasingly large earthquakes at an unusual rate, slowly heading towards the surface.
Scientists would also note ground deformation, if this unlikely event was to occur.
When I say ground deformation, I do not mean scientifically insignificant episodes of uplift,
such as what occurred from 2004 to 2009. During this period, the maximum rate of uplift observed
was only 2.8 inches per year! You can compare this with what happened before the 1980 eruption
of Mount Saint Helens. Each DAY, a part of the volcano experienced 5 feet of uplift!
The summary of these hazards are that no, yellowstone will not erupt soon, and you
should not worry that it will in the near future. I hope that you enjoyed this series of videos
on Yellowstone! My next video will cover an active volcano in Oregon,
Belknap crater. If you would like to suggest a topic for a future video, leave a comment below!