Over the course of the last week I kept running across the term “supervolcano”, so I thought it would be interesting to do a bit of research and see what, exactly, a supervolcano is.
A supervolcano is like a volcano, but super, right?
Well yes, essentially. There are different definitions and causes for volcanoes versus supervolcanoes, but you’ve got it pretty much in a nutshell there. Obviously, there’s scale: a volcano is usually measured by VEI, or Volcano Explosivity Index, and as long as that VEI is less than 8, it is still considered to be a regular volcano. Only once the VEI hits 8 does the volcano become a supervolcano.
How is the VEI measured?
It all has to do with how much ash the volcano spews out. If it’s spewing out less than 1,000 cubic kilometers of ash then it’s not super, but 1,000+ cubic kilometers and that’s a supervolcano. But that’s just the difference between a supervolcano and the rest of the volcanoes. Once you get below 1,000 cubic kilometers you get more classifications of volcanoes, which is pretty cool in and of itself.
Are there external triggers that could cause an eruption?
First of all, let’s define ‘external triggers’: earthquakes and drilling into the volcano are two examples. Could that cause an eruption? It certainly could, which is why we monitor supervolcanoes such as the one in Yellowstone. But will it definitely bring forth our doom? Not necessarily. Scientists are saying that it is just as likely that the magma will cause enough pressure internally to cause the eruption all by itself. But this takes time—there is a volcano in Bolivia that has been classified as a ‘supervolcano’ that has been building in pressure since 1992, but either the pressure could release some other way or it could explode… but they don’t know when: years, decades, centuries or even millennia.
Could Yellowstone have a super-eruption in our lifetime?
It’s possible, but unlikely. With all the different measurements that scientists are taking daily, we would likely see the precursors in advance to the super-eruption, such as increase in frequency of earthquakes, larger earthquakes, swelling in the earth’s surface, etc.
Say a supervolcano erupts, what would happen?
With 1,000+ cubic kilometers of material being produced, most areas nearby would be buried in approximately 1 kilometer of ash. After that there would likely be a volcanic winter which would result in harvests being lost for up to five years and billions of deaths.
Can supervolcanoes have smaller eruptions?
Yes, of course! There have been several smaller eruptions, usually resulting in lava flows or geysers.
If you would like to see how Yellowstone is monitored: click here!
A VEI Chart with lots of cool facts!