Jim McMahon

This past March, an Icelandic volcano called Mount Fagradalsfjall (fah-grah-DALS-fyatl) erupted for the first time in more than 800 years! For several weeks, lava spewed and flowed from long, deep cracks in the ground. Fountains of lava hardened into tall formations called spatter cones. Luckily, the eruption was far enough away from Icelandic residents to pose no danger.

The eruption wasn’t a surprise. In the weeks prior to it, scientists had detected more than 50,000 earthquakes nearby—far more than what is normal for the region. These quakes were caused by hot gases and magma, or molten rock, building up inside the volcano. “An eruption is nature at its most powerful,” says Icelandic geophysicist Magnús Tumi Gudmundsson (GOOD-mund-sun).