Eifel volcanism is still active. Researchers have measured that the earth rises there and is also pushed outwards from below. However, experts do not see the danger of an early outbreak.
Potsdam / Mainz (dpa) - The earth rises in the Eifel. Very little, by a millimeter a year - but for a long time. At the same time, the surface of the earth moves horizontally apart, as if something is pushing upwards from below. This has been proven for the first time by US scientists.
In a study, they evaluated measurement data from thousands of GPS antennas in Western Europe over 20 years - and thus came across new evidence of active volcanism in the Eifel region.
"The Eifel is the only region in the study in which the ground movement was significantly larger than expected," says lead author Corné Kreemer from the University of Nevada in Reno. "The results suggest that rising rock material could cause this movement of the soil." If you look at all the points, "it seems clear that something is brewing under the heart of Northwest Europe".
The last volcanic eruption in the Eifel was almost 13,000 years ago. According to researchers, it was as powerful as the Philippine volcano Pinatubo, which in 1991 catapulted five billion cubic meters of ash and dust into the air. The scientists in the "Geophysical Journal International" assume that magma accumulates at a depth of around 50 kilometers under the Eifel. The uplift area with the center of the Eifel also includes Luxembourg, eastern Belgium and the south of the Netherlands.
Only in early 2019 did German researchers prove that the Eifel is still an active volcanic system. Since 2013, they have detected eight series of low-frequency earthquakes at a depth of 10 to 45 kilometers under Lake Laacher. At the time, they wrote in the "Geophysical Journal Internetional" that magmatic fluids could rise from the upper mantle into the earth's crust.
However, the results of both studies did not mean that a volcanic eruption is currently imminent, says Torsten Dahm from the German Research Center for Geosciences (GFZ) in Potsdam, who was involved in the German study. The new US investigation is "a nice confirmation" that "there is activity in the Eifel". And from a different point of view: "For the first time it was possible to measure current uplifts in a larger area."
Dahm explains: "Something presses in the middle. It presses upwards and it also pushes away to the side. The way you imagine it when something pushes up from below." That fits with the assumptions "that there is an upward movement in the upper mantle from the mantle rock upwards". So far, it has been estimated from surface sediments that the soil only rises by 0.3 or 0.1 millimeters per year. "The rate determined by current measurements is higher."
"However, the studies do not change our assessments of volcanic hazards," says Dahm. The probability is there that there could be another Maar eruption or a small cinder cone in the Eifel. A major outbreak is expected sometime in the future "most likely again in the Eastern Eifel at Laacher See," estimates the geophysicist.
"We have observed microquakes, as it were, migrating to Laacher See. Which is a pretty clear observation." It is therefore important to "investigate this in more detail". The challenge is to "really map" the magma reservoir. This is the prerequisite for being able to better assess "how great the volcanic hazard actually is".
Measurements in the Eifel would have to be expanded further, says Thomas Dreher from the Rhineland-Palatinate State Office for Geology and Mining in Mainz. The earthquake service had already been strengthened this year, the measuring set in the Eifel intensified. "But we want to be more sensitive," he says. "And it's our turn." He sees no danger to people or infrastructure at all. "Not in the next 1000 years either."
Royal Astronomical Society communication on study
Current study in the "Geophysical Journal International"
German geological research center on earthquake and volcanic physics
German study from the "Geophysical Journal International" (2019)
