A new study utilizing advanced seismic imaging has provided the clearest picture yet of the magma chamber beneath the Laacher See volcano in Germany, a region that has seen increased earthquake activity in recent years[[1]], [[2]]. The research, published today in the Journal of Geophysical Research: Solid Earth, details the location, size, and a surprising orientation of the reservoir that last erupted approximately 13,000 years ago. This detailed analysis is crucial for assessing potential volcanic hazards in the region and understanding the origins of ongoing seismic swarms [[3]].
First Detailed Look Inside the Laacher See Volcano’s Magma Chamber
New data is providing an unprecedented view of the geological forces beneath the Laacher See volcano in Germany, confirming some existing theories about the region’s volcanic structure while also revealing unexpected details. Researchers have, for the first time, pinpointed the precise location, size, and depth of the magma reservoir that fueled the volcano’s last eruption approximately 13,000 years ago. “We now have the first high-resolution tomographic image of the upper 14 kilometers beneath the Laacher See Volcano,” said the research team.
The data reveals the magma reservoir lies roughly 6.2 miles (10 kilometers) below the surface – significantly deeper than previously estimated. Furthermore, the seismic anomaly beneath the Eifel volcano is oriented differently than expected. Instead of descending vertically, it slopes towards the Neuwieder Basin. “This channel-shaped anomaly, approximately 1.9 miles (3 kilometers) in diameter, extends from the Laacher See Volcano at an angle of 53 degrees southeastward into the depths,” the researchers report. This detailed mapping of subsurface structures is crucial for understanding volcanic activity and potential hazards.
Origin of Swarm Earthquakes Revealed
The research also sheds light on the thousands of micro-earthquakes in the Eifel region and potential fluid accumulations within the Earth’s crust. Most of the weak earthquakes occurred along a narrow, vertical zone between Laacher See and Ochtendung. However, earthquake clusters were also concentrated in the marginal areas of seismic anomalies – zones where seismic waves travel faster or slower than normal. According to the researchers, this could indicate increased temperature or pressure in these areas.
“Also unusual are the strong reflections of seismic waves at layer boundaries in the upper and lower crust beneath the Neuwieder Basin,” said Dahm. “The strength of the reflections suggests that fluids have accumulated in these layers.” Whether these fluids are magma or magmatic fluids remains unclear and will be investigated using improved evaluation methods.” (Journal of Geophysical Research: Solid Earth, 2025; doi: 10.1029/2025JB031338)
Source: GFZ Helmholtz Centre for Geosciences
December 19, 2025 – Nadja Podbregar
