A 24-ton truck shaking the earth to study a supervolcano? It sounds like the beginning of a mediocre Netflix series, but it's pure science.
A Yellowstone They called it “Vibroseis,” and that’s just a fancy way of saying, “Hey, let’s send vibrations underground and see what it responds to.” In 2020, while the rest of the world was busy with other matters, a team of seismologists from the University of Utah and New Mexico drove this steel giant along the park's Grand Loop Road. The goal? To truly understand what is stirring in the depths of one of the most monitored and feared supervolcanoes in the world. And the response was surprisingly reassuring.
Good vibes under the park
Artificial vibrations are a powerful tool for mapping what lies beneath our feet. When these waves are sent into the ground, they “bounce” in specific ways when they come into contact with rocks, liquids, and gases, allowing scientists to interpret their size, location, and composition.
The most effective method for these searches involves the use of “vibrating trucks”. (Remember the one in Germany (I told you about here?) These vehicles are equipped with huge metal plates positioned under the body that are pressed directly against the ground. They use hydraulic systems to generate low-frequency seismic energy waves, perfect (as in the German case) for detecting oil, gas, rare minerals or, in this case, magma.
Mike Poland, scientific manager ofYellowstone Volcanic Observatory, explained that it is not a matter of hitting the ground like a jackhammer. The plate makes contact with the ground and generates energy tuned to a frequency designed to bounce efficiently off the layers below.
For the avoidance of doubt: there is no cause for concern about accidental eruptions caused by these vibrations. As Poland pointed out, these machines are commonly used by the oil industry around the world without causing geological crises.
Yellowstone Supervolcano: The Structure of the Sleeping Giant
The research published in Nature has revealed two important discoveries about Yellowstone's magma chamber. First, it has mapped its top, finding it surprisingly flat and uniform, located more than two miles below the surface.
The second discovery concerns the composition of the chamber itself. Previous studies had concluded that yes, there is still molten magma, but about 75-80% of the chamber is solid. The research team expected to find a mixture of “melt and crystals” at the top, but the data revealed something different.
The analysis revealed an upper layer that acts as a lid, composed of solid crystals, molten magma and volcanic gases. The team described it as a “volatile-rich layer” filled with bubbles of magmatic gases. This structure, however, rather than representing a danger, actively prevents a violent eruption, allowing gases to gradually escape.
The opened can of soda
Poland used a good metaphor: it's like opening a can of soda so that the carbon dioxide rises to the surface and is released gradually, rather than building up until it explodes when the gas has no way out.
The magma chamber beneath Yellowstone is mostly solid. There is some gas accumulated at the top, but not much. This is a sign that pressure is not building, and it is a new and reassuring result.
This study adds another piece to what we already know about Yellowstone’s eruptive potential. Poland said it should be reassuring that so much research is giving scientists the same answer: All the evidence points to a mostly solid magma chamber that doesn’t build up pressure.
Supervolcano, a pinch of comfort
The nature of Yellowstone's magma chamber may change in the future, but all current evidence points to low eruptive potential. There is not much molten magma moving inside, and most of the magma gases are rising toward the surface.
If this situation were to change, it could increase the likelihood of a Yellowstone eruption. However, Poland and most other scientists do not expect this to change in the near future. Monitoring continues to be done to be ready if something were to change, but for now the conditions needed to generate a volcanic eruption simply are not there.
Yellowstone's good news goes hand in hand with recent discoveries on Campi Flegrei in Italy, the other supervolcano that worries millions of people (including me). There too, new studies indicate that the situation could be less dramatic than expected.
Ironic, isn't it? We spend our days fearing impending catastrophes, while supervolcanoes sit there, slumbering, being studied by enormous vibrating trucks without batting an eyelid. Perhaps we should take a cue: less agitation, more solid stability.
And if you really want something to worry about, focus on your bills: those are in a constant state of eruption.
