Germany: a danger of volcanic eruptions?

In the wake of the Fukushima disaster on March 11th, 2011, Chancellor Angela Merkel, a chemical physicist by profession with a Dr. rer. nat. (University of Leipzig, 1986, summa cum laude) took the decision to stop eight nuclear plants in Germany and initiated a gradual, full exit of Germany from nuclear energy by 2022. A wise decision, for more reasons than one... The following article on the - seemingly remote - danger of volcanic eruptions in Germany does not take into account the general geological instability of the Rhine graben, which has been the site of severe earthquakes in historic times.

(See also: Fukushima: Silenced Truth)

The Eifel is an idyllic low mountain range in West Germany, bordering on the Rhine to the East and the Moselle River to the South, with its highest elevation a mere 747m at the Hohe Acht.

Yet, German geologists have been asking themselves: does the Eifel present a volcanic threat? This possibility is beginning to gather strong support in expert circles, ready to go on the offensive. The situation could turn from quiet to catastrophic in a matter of months. The volcanoes of the Rhineland are not subjected to close surveillance. One expert proposes to use ants as an early warning system.

A huge explosion rattling doors and windows from Frankfurt to Cologne... In Bonn and Coblence, people can see the origin of the noise, as a dark red cloud rises on the horizon, and the Eifel hills seem to be ablaze. Then ashes and stones rain from the sky.

While fire-fighters and emergency task-forces debate hectically and helplessly, burning rivers of melted stone roll into the valleys. Lava engulfs villages, converging on the Rhine. The Rhine waters are dammed up all the way up its tributaries and the Upper Rhine valley is inundated. From Strasbourg to Mannheim to Frankfurt, nuclear plants, chemical factories and airports are submerged.

It would seem that a volcanic eruption in Germany could be at most the stuff of science-fiction. Geologist Ulrich Schreiber of the University of Duisburg paints in a novel, Ants on the Run, the dramatic consequences of an Eifel eruption. But Schreiber doesn't leave it at fiction. The expert points out that the risk of an eruption in Germany has been underestimated. In articles and on conferences, he presents his thesis that ant migrations could be used as an early warning system in the catastrophe.

Lakes of the Eifel - they all originated as volcanic craters

It is the first time that a scientist dares to expressly classify the Eifel as a danger zone - taking the risk to be laughed down as a catastrophe-monger. It must be said that a volcanic eruption in Germany appears unlikely - the last one goes back 11,000 years.

But instead of taking their distances from Schreiber, his expert-colleagues agree that Schreiber's book presents merely the results of the latest research. "The scenario he is describing is possible," says seismologist Klaus-Günter Hinzen of the University of Cologne, who keeps an eye on earth movements in the Eifel.

"Of course, the threat is not comparable in immediacy with the one of Vesuvius," Schreiber says. There exist no signs of an imminent eruption. But this situation could change within months. Moreover, one tends to ignore the fact that in the Rhine area, heavy industry and millions of people are settled close to an active volcano. The worst case scenario needs to be considered. Emergency plans need to be established for the case of a volcanic eruption in the Eifel.

The experts are agreed that eruptions will occur in the Eifel again. Although nobody can say when: "Possibly, it will take some millenia, but it could take a few months, just as well," Hinzen says. It is probable that the Eifel is now at the beginning of a new phase of activity, declares volcanologist Hans-Ulrich Schmincke of the Leibniz-Institute of Marine Science in Kiel, who has long been observing the Eifel volcanoes.

The last quiet phase finished abruptly. 12,900 years ago, a gigantic eruption shook the Eifel. "Presumably, people were just as relaxed at the time as we are today," says Schmincke. "The Ur-Rhinelander certainly did not expect a volcanic eruption, the last one having taken place 100,000 years before." But one day, rising magma met the groundwater. The blast of the ensuing explosion broke all the trees in the area like matches. Ashes shot 30 kilometers high and reached all the way to Sweden carried by the southwest wind.. West Germany was covered in a grey rain of ashes.

Lava dammed up the Rhine near Andernach, the region of today's Coblence was underwater. After a few days, the lava dam broke. A floodwave rolled all the way down to the Netherlands, streams of mud and water masses several meters deep buried the Rhine Valley. Prehistoric tools and skeletons trapped in the debris-layers show that the Ur-Rhinelander had been taken by surprise by the catastrophe. After the magma reservoir at the spot of the eruption had emptied itself, the earth gave way - the depression is now filled by the Laacher See.

Chemical complexes and nuclear plants in the Rhine Valley. The area in blue shows the possible back-up of water if a lava flow from an Eifel volcano dammed up the river. The old French nuclear plant of Fessenheim, near Mulhouse, which should have long been de-commissioned and which is situated close to an active geological fault, is not even indicated.

The last eruption occurred 11,000 years ago and remained regionally limited, it brought the formation of the Ulmener Maars. In the Eifel, one can find traces of hundreds of volcanic eruptions. Their deposits hardened to ash- and lava stones, which have been quarried intensively since Roman times. A trail of 50 smaller craters stands as a witness to magma-explosions. The so-called Eifel-Maare form nowadays a picturesque landscape of lakes.

Meanwhile, experts who have been examining the volcanic layers wonder about the 11,000 year lull. For the eruption of the Laacher-See volcano 12,900 years ago had been the first in 100,000 years. Much points to the fact that it marked the beginning of a long series of eruptions which is still running. For the last three phases of eruption in the past 450,000 years lasted around 10,000 years each, scientists around Hans-Ulrich Schmincke have found out.

All over the wolrd, volcanoes tend to follow similar cycles. Should this also be the case in the Eifel, "it is possible that in the most immediate future" a number of eruptions could be expected, the geophysicist Gerhard Jentzsch of the University of Jena warned as early as 2001, in a expert opinion written for the government.

Locally limited eruptions, like those at the Ulmener Maar, appear to scientists as the most likely scenario. For this to happen, only a little more magma would need to accumulate underground. This could happen in a matter of months, explains geophysicist Joachim Ritter of the University of Karlsruhe, who has plumbed the underground with sound-waves in the frame of the "Eifel-Plume-project." Should the gas pressure increase, the 1000°C stone mush could shoot up, declares Ritter.

The subterranean Eifel is moving. Especially between the Laacher See and Coblence, small earthquakes are regular reminders of the lurking danger. Possibly, rising groundwater, which is being heated up by the magma reservoir 50 km down, is triggering the vibrations. The underground around the Laacher See reaches a temperature of 60 to 70 degrees at a depth of one kilometer - an unusual reading.

In the 1990s, scientists saw in these phenomena the tailing-out of Eifel volcanism. Today, they reinterpret the signals as a sign of ongoing activity. Another sign of life from the Eifel volcanoes bubbles up from the Laacher See: bubbles in the water signal carbone dioxide originating from the magma. As it is rising, it is thought that magma releases an increased amount of CO2.

Geologist Schreiber is of the opinion that ants would be first to have warning of an impending eruption. Just as chimney-fires would chase away storks from chimneys, carbon dioxide drives out insects from their nests, which they tend to install preferably on tectonic fissures.

At first, Schreiber's theory elicited loud protests from ant experts. But since he has presented his proofs to his colleagues in papers and in seminars, the opposition has abatted. Schreiber and his colleagues have offered their observations to scientific publications.

Should the Eifel-ants leave their heaps en masse, it would be an alarm signal, Schreiber says. Otherwise, there might not be any other signs of an increase in the sub-terranean magma. For there are but few measuring instruments installed in the Eifel. "A systematic monitoring of the volcanoes is not possible," deplores Schreiber.

based on an article by Axel Bojanowski