Research Roundup: GPS reveals volcanic activity under Europe

Scientists have discovered new evidence for active volcanism next door to some of the most densely populated areas of Europe. The study crowdsourced GPS monitoring data from antennae across western Europe to track subtle movements in the Earth’s surface, thought to be caused by a rising subsurface mantle plume.

The Eifel region lies roughly between the cities of Aachen, Trier and Koblenz, in west-central Germany. It is home to many ancient volcanic features, including the circular lakes known as maars. Maars are the remnants of violent volcanic eruptions, such as the one that created Laacher See, the largest lake in the area. The explosion that created the lake is thought to have occurred around 13,000 years ago.

The mantle plume that fed this ancient activity is thought to still be present, extending up to 400 kilometers (km) into the earth. However, whether or not it is still active is unknown. “Most scientists had assumed that volcanic activity in the Eifel was a thing of the past,” said Corné Kreemer, lead author of the new study. “But connecting the dots, it seems clear that something is brewing underneath the heart of northwest Europe.”

An aerial view of Laacher See, a volcanic caldera lake with a diameter of 2 km in Rhineland-Palatinate, Germany. Created by volcanic activity, maars like this are also found in other parts of Europe and on other continents, but Eifel-Maars are the classic example worldwide. (Photo: bbsferrari/iStock / Getty Images Plus/Getty Images)

In the new study, the team — based at the University of Nevada, Reno and the University of California, Los Angeles — used data from thousands of commercial and state-owned GPS stations all over western Europe. The research revealed that the region’s land surface is moving upward and outward over a large area centered on the Eifel, and including Luxembourg, eastern Belgium and the southernmost province of the Netherlands, Limburg.

“The Eifel area is the only region in the study where the ground motion appeared significantly greater than expected,” said Kreemer. “The results indicate that a rising plume could explain the observed patterns and rate of ground movement.”

The new results complement those of a previous study in Geophysical Journal International that found seismic evidence of magma moving underneath the Laacher See. Both studies point towards the Eifel being an active volcanic system.

The implication of this study is that there may not only be an increased volcanic risk, but also a long-term seismic risk in this part of Europe. The researchers urge caution, however. “This does not mean that an explosion or earthquake is imminent, or even possible again in this area. We and other scientists plan to continue monitoring the area using a variety of geophysical and geochemical techniques, to better understand and quantify any potential risks.”

GPS observations of ground movement under the Eifel area. Colors represent contoured vertical motion inferred from GPS station data, and white and black arrows indicate the direction in which the crust is horizontally stretching or compressing, respectively. The highest upward motion of ~1 mm per year is found near the Eifel volcanic field. (Image: Study authors)

Citation: “Geodetic evidence for a buoyant mantle plume beneath the Eifel volcanic area, NW Europe” by Corné Kreemer, Geoffrey Blewitt, Paul M. Davis. Geophysical Journal International, Volume 222, Issue 2, Aug. 1, 2020, pp. 1316–1332, https://doi.org/10.1093/gji/ggaa227