It’s fair to say that people are enthralled by volcanoes. We get many questions about them. What would happen if Yellowstone caldera erupted again today? (If it’s a powerful blast, then spoiler alert: nothing good.) Can we throw away all our trash in volcanoes? Do volcanoes produce more carbon dioxide than humans on a similar timescale?
Just in the last week or so, a question has appeared at a curiously high frequency. Namely, what would happen if someone detonated a nuclear bomb at the surface of the most famous supervolcano in the world?
Some people just want to watch the world burn, I suppose.
So, let’s get this out of the way as quickly as possible then: I don’t know, but probably nothing. It would have much the same effect as firing a nuclear weapon at a hurricane, a question that the US government’s top scientific agency has already gleefully answered.
Accidentally or intentionally triggering a volcanic eruption is a nothing more than a thought experiment at this stage, and some stellar science communicators have already given it a ponder in their own idiosyncratic way. Each time, slightly different conclusions have been made.
As you may have expected, this particular experiment – placing a nuclear weapon atop a supervolcano – hasn’t been run in the real world before. At no point in human history has anyone been mad enough to try this, but all the current evidence suggests that, when it comes to something like Yellowstone, it would be like firing an air rifle at a tank.
Ultimately, detonating one of America’s most powerful nuclear weapons in the middle of Yellowstone National Park will simply ruin the beautiful landscape, which we can all agree would be a rather terrible thing to do.
Yellowstone supervolcano is fascinatingly massive, with a two-step magma chamber system that in total contains about 58,667 cubic kilometers (14,075 cubic miles) of partially molten rock. Although a high-end, paroxysmal eruption won’t even get close to bringing about the end of the world, it would create a nationwide catastrophe with global ramifications.
Generally speaking, there are a few ways in which you can trigger a volcanic eruption. Crack the overlying rock, and the highly pressurized and eruptible part of the magma chamber would froth up and explosively fragment as it rushes to the surface.
You can also add more dissolved gases – like water – into the magma, as well as cool it a little to induce crystallization; both would have the effect of supersaturating the magma in dissolved gases, which forces them to exsolve into bubbles, adding buoyancy and amping up the internal pressure of the magma. Those are the basics.