What's Going On At Yellowstone?


Robin Andrews

Science & Policy Writer

Castle Geyser, a geothermal feature powered by the magma brewing below. Poul Rilshede/Shutterstock

That earthquake swarm that’s rocking Yellowstone National Park has reached at least 1,284 individual tremors. If this continues any longer, then the supervolcano hiding beneath the surface will catastrophically erupt, America will be buried in ash and lava, and the world will end – scorched by fire and burned to a crisp.

Only joking. Despite the fact that the earthquake swarm is refusing to die down, there’s absolutely no reason to be concerned. Yellowstone’s caldera will not collapse and erupt, at least not in the way everyone’s imagining that it might.


As we explained a couple of weeks ago, these earthquakes are not being caused by the movement of magma.

It’s more likely that they are taking place because several minor fault lines streaking across the National Park are experiencing some friction, stress build up and release. There’s a good chance, according to the United States Geological Survey (USGS), that groundwater of heated mineral-rich fluids are being squeezed through these faults, which is causing them to fracture ever so slightly.


Sometimes, this fluid injection causes rather powerful quakes, like the 4.5M one back in June, or the 3.6M one just this Tuesday. Mostly, this phenomenon produces earthquakes that are so weak that they are, thanks to a weird mathematical quirk, registering as having negative magnitudes.

Even if moving magma was the cause of the swarm, this wouldn’t be a reason to panic either. Yellowstone is certainly dormant – in that it doesn’t have any eruptive activity ongoing right now – but this still means that its magmatic plumbing system is still churning away.


It sits above an upwelling plume of superheated mantle material. The crust is continuously being melted, and magma is always being generated. Magma, as you are probably aware, does not just sit there. It moves around, but that doesn’t mean it’s about to explode onto the surface.

Even if ultimately there is an eruption, it will be a lava flow, not a supervolcanic planet-changing blast. The likelihood of any eruption at all taking place at Yellowstone right now is about 1 in 730,000, and it is more likely to be harmless than devastating. Although a supervolcanic blast is a possibility, it’s extremely unlikely that it will happen in the next few days, years, or even centuries.


These earthquake swarms, by the way, are common in volcanically or seismically active zones. Back in 2010, there was a swarm that produced more than 2,500 events – and as you might have noticed, the world didn’t end back then either.

In summary, you’ll be fine. Science says so.


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