A bubbling supervolcano hotspot is under what is today Yellowstone National Park in Montana. Geysers of hot water and steam gush to the surface throughout the park, a constant reminder of what lies below. Sometimes the thermal explosions are seriously dangerous and have killed people who got caught in the outburst.
Since Christmas, geologists have been recording an unusual number of earthquakes underneath the park. The activity was significant enough to note, though at this point, they do not think it signals an imminent supervolcanic eruption.
If it did, volcanic ash would cover most of the continental United States, and probably plunge the world into a volcanic winter.
If you are short of something to worry about, Yellowstone might help fill the void. The supervolcano under Yellowstone has been erupting on average every 600,000 years for the last 16 million years. The last time it exploded was 630,000 years ago.
It’s a little overdue.