Deep underground, hundreds of earthquakes have been recorded

More than 500 small earthquakes have been recorded beneath Lake Laach in western Germany over the past year, according to recent studies. These tremors, known as deep low-frequency seismic events, have raised concerns among scientists who monitor the region near the extinct volcano that last erupted approximately 13,000 years ago. The activity has reignited interest in the volcanic system under the Eifel region, which contains more than 100 volcanoes and is considered one of Europe's most active geological areas. The quakes were detected using a network of monitoring stations installed around Lake Laach, which lies within the crater of the Laacher See volcano. This volcano was responsible for a massive eruption that spread ash as far north as Sweden and south into northern Italy. Scientists warn that while the current activity does not indicate an imminent eruption, it suggests ongoing geological processes beneath the surface. Between September 2022 and August 2023, researchers documented over 500 micro-earthquakes occurring at depths ranging from 12 to 14 kilometers below the Earth’s crust. These events, classified as deep low-frequency (DLF) earthquakes, are typically associated with the movement of magma-related fluids such as water, oxygen, sulfur compounds, and halogens. Such movements can trigger seismic activity and provide clues about potential future eruptions. In late October 2025, a cluster of 92 micro-quakes occurred in just 12 hours, marking an unusual surge in seismic activity. The strongest of these had a magnitude of 0.9, barely perceptible to humans. Researchers noted that four distinct clusters of similar DLF earthquakes had been identified in the eastern Eifel area over the past five years. Despite this increased activity, experts emphasize that there is currently no indication of an imminent volcanic eruption. Studies analyzing magma samples from the last major eruption suggest that the upper magma chamber beneath Lake Laach may have taken roughly 30,000 years to fill before the previous eruption. This long timescale implies that any new buildup would take similarly extended periods. Scientists from the German Research Centre for Geosciences (GFZ) have conducted radio-magnetotelluric measurements around Lake Laach since 2024. These tests revealed continuous emissions of carbon dioxide from the Earth’s mantle, another sign of ongoing geological activity. However, no evidence has yet been found of significant uplift in the ground surface, which would be a clear indicator of rising magma. Torsten Dahm, head of the department for earthquake and volcano physics at GFZ, explained that DLF earthquakes are observed globally under active volcanoes such as those in Iceland, Japan, and Kamchatka. He emphasized that while the current findings are noteworthy, they do not necessarily signal an immediate threat of volcanic activity in the region. Martin Hensch, lead author of a 2019 study published by the Association of State Seismological Services, highlighted the importance of continued monitoring. His research indicated that the presence of magma chambers beneath the Earth’s crust could slowly accumulate over time, potentially leading to future eruptions. Nevertheless, he stressed that the current data does not support expectations of imminent volcanic activity. Joachim Ritter from the Institute of Geophysics at the Karlsruhe Institute of Technology added that the absence of high-frequency seismic activity and visible ground deformation further reduces the likelihood of a near-term eruption. He noted that such signs would be unmistakable if large volumes of magma began moving upward through the crust. Researchers continue to analyze the data collected from the monitoring stations and the geochemical signals detected in the surrounding area. Their goal is to better understand the mechanisms driving the current seismic activity and assess whether it could eventually lead to renewed volcanic activity in the region.