Why do volcanoes erupt differently?

Geosearch from Potsdam Researchers calculate: where do volcanoes erupt?

In the south of Italy, near Naples, are the Campi Flegrei - the Phlegraean, or in German burning fields. Remnants of a largely underground volcano with a huge magma chamber. If that breaks out, there could be a global catastrophe, fears physicist Dr. Eleonora Rivalta. But predictions of where the lava will break out of the earth have so far been very vague. The researcher illustrates this on a shooting range: "When I shoot with a rifle, I know the equation for movement so well that I don't need any statistics at all. I shoot, I score."

Probabilities as a basis ...

It is different with magma. It also shoots out of the ground, but is hindered and slowed down on its way out. In this process, there is no equation, no clear calculation method to predict where the magma will emerge: "But what I can do is calculate the probability based on a lot of data," explains Eleonora Rivalta.

... and physics on top

There is a lot of data from the past. The researchers also know where the magma fields lie underground. You can see this on satellite images, as well as how and whether you are moving. But volcanoes are unpredictable. The hot magma has the power to cut its way underground through the rock, sometimes over ten kilometers. In order to still predict the path, the scientists from the German Research Center for Geosciences and colleagues from Italy add a second discipline. The physic. They calculate the path of the underground magma flow based on the tectonic plate movement.

Another component is the weight of a volcano: "A mountain has a great weight and compresses the crust below, another great tension. All of these tensions add up and interact," explains Rivalta.

And now comes the real work. A software developed by the Potsdam researchers now takes all available data, where the lava used to emerge from the earth, the tectonic situation under the volcano before it erupted, and simulates the situation before the last volcanic eruption. "I do that ten million times until I find a field of tension that can link the magma chamber in all places where I had previous eruption sites," says the scientist.

Ready to use in a few years

At some point the program will calculate exactly the places where the lava emerged from the earth. This is then the starting point, the calibration of the program in order to use it for predictions. The burning fields near Naples were the first test object, new applications are planned in Sicily and a volcano in the Indian Ocean. The physicists at the German Research Center for Geosciences estimate that there will still be two or three years. Then the program could be so user-friendly that researchers around the world could use it for predictions.

The results of the current research have been published in Science Advances magazine.