Ask A Scientist: How Do You Know When A Volcano Will Erupt?

Volcanoes! Everyone loves volcano news, but living close to one when it erupts, not so much. That’s why Iceland has a team of scientists who dedicate their lives to monitoring their activity and letting Civic Protection know when one of them looks ready to erupt. But given how notoriously unpredictable volcanoes are, how exactly do they do that? We asked Baldur Bergsson, a specialist in monitoring at the Icelandic Met Office, how experts know when a volcano is ready to pop.

“There’s no way you can say ‘oh, this volcano will erupt in two years’ or whatever,” Baldur says. “What we’re focusing on is what happens just before an eruption. This could be maybe a month before or, in the case of Hekla, hours before. Each volcano is different. We try to define what happens before an eruption, and a lot of our knowledge comes from past eruptions, document that, and adjust our monitoring techniques for each individual volcano. Of course, this is really difficult when it comes to volcanoes that might erupt every 100 or 200 years. In those cases, we just have to go with how things generally work. But for a volcano that erupts more frequently, like Grímsvötn or Hekla, we have a pretty good idea of how things escalate.”

You can read the full interview with Baldur, and our adventures tagging along as he measures possible volcanic activity at a couple of sites here.