Roman aqueduct reveals earthquakes

Former aqueduct provides evidence of historical Erdst e in the Rhineland

Among other things, the Romans built a long bridge over the Swist for their aqueduct - this simulation shows what it looked like. © public domain
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Aqueduct as a whistleblower: About 1.900 years ago, the earth shook violently in the Rhineland. As researchers report, there were one or more major earthquakes in the region at that time. At least damage to the Eifel aqueduct indicates this - a water pipe built by the Romans. The identification of this historic quake, according to the team, should contribute to a better risk assessment of future earthquakes.

The Romans are known for their advanced water system: Fresh drinking water they led in large aqueducts over long distances to their cities. Also built in the first century Eifel aqueduct is a relic from Roman times. It is considered the longest aqueduct north of the Alps and was in operation for about 190 years.

The Romans led lime-laden water from the vicinity of Nettersheim through the Eifel aqueduct over a distance of about 95 kilometers to Cologne. "Calciferous water was in demand because pipes in the Roman villas were made of lead, " explains Gösta Hoffmann from the University of Bonn. "The lead was toxic, the lime dressed the pipes like a protective layer."

The researchers from the University of Bonn use archaeological publications to trace the course of the Eifel aqueduct. © Eva Heumann-Lange

Line as "spirit level"

On its way to Cologne, the former aqueduct crosses several geological faults. These are rupture or break points in the rock, where parts of the earth's crust pass each other when they are under tension - causing earthquakes. Hoffmann and his colleagues have now used the Eifel aqueduct as a kind of spirit level for these fault zones. Your idea: If there had been a major earthquake since the construction of the line, then the damage to the line must be recognizable.

Since only remains of the water pipe are preserved today, the scientists had to use additional information for their project. Among other things, they used laser-assisted measurement data from the state of North Rhine-Westphalia and used it to create a three-dimensional gel model. In it they inserted the course of the Roman aqueduct recorded in earlier publications. display

Planning error or Erdsto as cause?

In fact, the evaluation revealed incidents that the research team investigated more closely on site: In the Mechernich Forest, archaeologically documented repair measures can be recognized. Over a distance of four kilometers, the pipeline was routed twice, where one of the two cable runs at one point has a step of 35 centimeters in height.

Archologists have so far assumed that the Romans had built two different sections of the aqueduct towards each other and then realized that the connection did not fit. Then the temporary diversion was built. However, Hoffmann and his colleagues consider another cause to be more plausible: an earthquake. Because, as they report, there is a geological fault at the exact point in question.

"One or more quakes"

"It must have been one or more major earthquakes, because only then can such damage to the line occur, " says Hoffmann. An additional indication of such a relationship provides the researchers according to the Kakush hle in Eiserfey. There, in the same period from the first to the second century, blocks of blankets erupted into Roman layers of the cave.

The region studied by the scientists is considered vulnerable to earthquakes, as the earth's crust is under tension there. Most recently, with the earthquake of Roermond in 1992, there was a stronger earth movement in this area. An earthquake in D ren in 1756 and in Verviers in 1692 are also historically recorded.

The earthquake that has now been proven by Hoffmann and his colleagues, one and a half years ago, joins this list of known historical earthquakes - and could thus provide valuable information for the future. "With every additional documented event, we can better assess the risk of another quake in the region, " concludes Hoffmann. (International Journal of Earth Sciences, 2019; doi: 10.1007 / s00531-019-01766-y)

Source: Rheinische Friedrich-Wilhelms-University Bonn

- Daniel Albat