Every person in our country has at least heard of Yellowstone National Park but what about it makes it so special? Yellowstone is just one large volcano and although it hasn’t erupted for 10,000 years, it still gets a lot of media attention. Most of those media outlets are stating that Yellowstone is going to erupt soon and destroy all of civilization. However, there are no signs that the Yellowstone volcano is heading towards an eruption. People believe that we won’t be able to tell when this giant erupts but it’s just a volcano. The only thing that sets it apart from other volcanoes is its massive size. The signs of an eruption for Yellowstone would be identical to those from the eruption of Mount St. Helens.
Gas Comes To The Surface
Yellowstone already releases a lot of gas through the springs and geysers but the gas that would show an impending eruption would contain more carbon emissions. One thing that may happen is called uplift and it’s where the magma under the surface shoves existing rock out of the way and pushes the surface up. However, just because the ground is rising, doesn’t mean that Yellowstone is going to erupt. Magma can fill in under a volcano, causing uplift yet never reach the surface.
Other processes can also make the surface rise, like changes in the hydrothermal system which is when hot water flows around the magma. The uplift of a volcano needs to be extreme in order to be concerned. An extreme case is called a “restless caldera” when the surface actually rises and falls frequently due to the water flowing underground or the amount of magma entering the system.
As stated before, magma takes up space and when it pushes rocks out of the way, it can cause some earthquakes on the surface. These are either due to cracking rocks or the actual magma moving in the conduit. Seismologists look for these rock fracturing earthquakes and for “harmonic tremor” related to the magma’s movements. As these increase, the chances that the magma is moving increases. Shallow earthquakes mean that the magma is getting closer to the surface and may signal an impending eruption. However, most volcanoes have earthquakes all the time so there isn’t much to be concerned about and for volcanoes that are considered as a “restless caldera” like Yellowstone, they can happen more frequently. Magma is extremely hot as well so even at a place like Yellowstone where the magma is cooler, it is still at 750oC or higher. Since the surface is cold, you can see the steam from the magma’s heat in the form of increased activity at the hot springs or geysers. Thermal signals, usually measured by infrared cameras, can also show evidence of the caldera’s heat.
There needs to be multiple lines of evidence in order to say for sure if there is an eruption coming. But what if Yellowstone were to erupt? Well, if Yellowstone was heading towards a new eruption, we might expect to see all four of these factors in the same area. However, with any volcano, it’s very difficult to predict the timing and the size of the eruption it would create. The three giant eruptions that have happened at Yellowstone over the past two million years are uncommon. If the caldera did erupt there would be tons of ash that would cover much of the western United States and the impact would be felt all over the world.
On the other hand, the Yellowstone caldera is being closely monitored by the Yellowstone Volcano Observatory so there is no need to worry. Right now, the caldera’s status is green, the lowest and the only status it has ever been since the USGS started giving alert statuses. Yellowstone will always be a restless giant with geysers constantly changing their behavior. It’s the nature of the giant and you might as well enjoy your time at Yellowstone National Park because it’s not going anywhere anytime soon.