VolcanoesUnravelling the When, Where and How of Volcanic Eruptions

By Sandrine Ceurstemont

Published 4 March 2021

There are about 1,500 potentially active volcanoes worldwide and about 50 eruptions occur each year. But it’s still difficult to predict when and how these eruptions will happen or how they’ll unfold. Now, new insight into the physical processes inside volcanoes are giving scientists a better understanding of their behavior, which could help protect the 1 billion people who live close to volcanoes.

There are about 1,500 potentially active volcanoes worldwide and about 50 eruptions occur each year. But it’s still difficult to predict when and how these eruptions will happen or how they’ll unfold. Now, new insight into the physical processes inside volcanoes are giving scientists a better understanding of their behavior, which could help protect the 1 billion people who live close to volcanoes.

Dome-building volcanoes, which are frequently active, are among the most dangerous types of volcanoes since they are known for their explosive activity. This type of volcano often erupts by first quietly producing a dome-shaped extrusion of thick lava at its summit which is too viscous to flow. When it eventually becomes destabilized, it breaks off and produces fast-moving currents of hot gas, solidified lava pieces and volcanic ash, called pyroclastic clouds, that flow down the sides of the volcano at the speed of a fast train.

“The hazards associated with them can be very spontaneous and hard to predict,” said Professor Thomas Walter, a professor of volcanology and geohazards at the University of Potsdam in Germany. “That’s why it’s so important to understand this phenomenon of lava domes.”

Little is known about the behavior of lava domes, partly because there isn’t much data available. Prof. Walter and his colleagues want to better understand how they form, whether they can vary significantly in shape and what their internal structure is like. Over the last five years, through a project called VOLCAPSE, they have been using innovative techniques to monitor lava domes by using high resolution radar data captured by satellites as well as close-up views from cameras set up near volcanoes.

“Pixel by pixel, we could determine how the shape, morphology and structure of these lava domes changed,” said Prof. Walter. “We compared (the webcam images) to satellite radar observations.”

Time-lapse

The project focused on a few dome-building volcanoes such as Colima in Mexico, Mount Merapi in Indonesia, Bezymianny in Russia, and Mount Lascar and Lastarria in Chile. It partly involved visiting them and installing instruments such as time-lapse cameras powered by solar panels that could be controlled remotely. If a lava dome started to form, for example, the team could tweak the settings so that it captured higher resolution images more often.