Beneath the towering forests and thundering waterfalls of Wyoming’s Yellowstone National Park, something scary lies in slumber. The steaming pools, bubbling mud pots and fountaining geysers testify to high temperatures not far below the surface – hardly surprising considering that the park is perched above one of the planet’s biggest and most dangerous volcanoes. But only recently has the extent of the vast magma chamber below been revealed.
When seismic waves travel through the ground, they pass more slowly as they travel through fluids, such as magma. By using new data on the behaviour of seismic waves spawned by around 4,500 earthquakes, researchers have been able to build the clearest picture yet of the magma hidden within the crust at Yellowstone. It points to a reservoir two-and-a-half times larger than previously thought.
Worryingly, the chamber contains sufficient
