A new study explains why even gas-rich, supposedly explosive volcanoes sometimes erupt quietly instead of blowing apart.

It was a quiet Sunday morning, at 8:32 a.m., 38 years ago when Mount St. Helens blew its top, sending tons of ash into the sky. The volcano had been quiet since the 1850s, but in 1980, geologists were ...

May 18 marks the 45th anniversary of the catastrophic eruption of Mount St. Helens in southwestern Washington. The blast in 1980 killed dozens of people and reshaped the volcanic peak in the Cascade ...

Learn how stress inside a volcano can make gas bubbles form early, helping explain why some eruptions stay quiet instead of ...

The explosiveness of a volcanic eruption depends on how many gas bubbles form in the magma—and when. Until now, it was ...

What is that coming out of Mount St. Helens? Is it ash? The National Weather Service (NWS) in Portland assured everyone that although ash is circulating, the mountain is not erupting. Strong winds ...

Volcanoes are now more closely monitored. We have a good chance now of determining when a volcano becomes restless,” says Don Swanson, a volcanologist reflecting on the lessons learned from the 1980 ...