The Netherlands’ new Deep Earth Data Act opened a cache of cross-border monitoring readings on Saturday, revealing ground movement and a burst of small earthquakes near Laacher See, the volcanic lake in western Germany. Scientists analysing the data say the signs could mark magma rising beneath the Eifel region, about 90 km (56 miles) from the Dutch border.
A research team led by the fictional Rhine Basin Geophysical Service measured 3.8 cm (1.5 inches) of uplift over 11 days across an area of roughly 11 km² (4.2 square miles). It also counted 2,400 tremors in six days, most between 4 km and 7 km (2.5 and 4.3 miles) below the lake. Neither figure alone proves an eruption is coming.
The new readings
The law requires Dutch-funded deep-earth projects to publish raw measurements, including readings from instruments deployed across the border. That released a set of tilt and seismic data from a research programme around Laacher See. Volcanologist Marta Kaczmarczyk-Cieślak said independent satellite measurements also showed the ground rising, while gas readings at two lakeside vents had increased sixfold since September.
“We are not saying an eruption is certain, but the pattern is moving in the wrong direction,” Kaczmarczyk-Cieślak said. If the tremors continue to climb towards the surface, she added, scientists could have “days, not weeks” to assess the change. Her team’s watch window runs from 29 October to 5 November, but she stressed that no reliable method can give an exact eruption date.
If the tremors continue to climb towards the surface, scientists could have days, not weeks.
Marta Kaczmarczyk-Cieślak, volcanologist
The worst-case model, prepared for a large explosive eruption, projects ash deposits of 10 cm (4 inches) or more within 50 km (31 miles) of the lake and several centimetres in parts of Dutch Limburg. A plume could force widespread flight cancellations and disrupt transport and water supplies. Researchers stress that this is a planning scenario, not a forecast of what will happen.
Officials urge caution
Dutch risk director Daina Auškāps said the government had asked Limburg’s emergency planners to review shelter guidance and supplies of protective masks, but had not ordered evacuations or school closures. “There is no confirmed eruption signal, and the public should not treat a worst-case model as tomorrow’s weather,” she said. German authorities have raised their monitoring level but have not advised residents to leave.
That caution has angered researchers who say the public deserves a clearer account of how little is known. Geophysicist Jan Pfleger, who reviewed the released readings, said the rise in tremors and gas output was “a real change, not a software glitch”. He called for local authorities to prepare for ash disruption now, rather than wait for a definitive signal that might arrive too late for orderly planning.
Laacher See last erupted about 12,900 years ago, spreading ash across parts of Europe. It is not classified as a supervolcano, and scientists say its long quiet period cannot by itself predict when it might erupt. But a large eruption could affect air travel well beyond the region, while fine ash can damage engines and contaminate water systems.
The Dutch law was designed to make measurements from the deep subsurface public, not to issue volcanic alerts. Its first day has instead exposed a fast-moving argument over who should warn residents when evidence is alarming but uncertain. Auškāps said officials would publish an updated assessment on Monday; Kaczmarczyk-Cieślak said her team would release its next analysis as soon as the weekend’s readings were checked.
