When you have 400 earthquakes on top of one of the largest supervolcanoes on Earth, people pay attention.

And since the day after Christmas, that's what has happened at Yellowstone National Park. Scientists are seeing what they call a "swarm" of low intensity earthquakes -- the largest since the 1980s. The biggest quake had a magnitude of 3.9, below the level that can cause damage.

But the earthquakes have made worldwide news because the park lies on a giant caldera, the crater of a volcano that scientists say could one day explode and destroy most of North America and freeze the rest of the world under a shroud of ash for up to two years. Still, the latest earthquakes are nothing to fear, said park geologist Hank Heasler.

Read the full story at idahostatesman.com.