Lakes provide answers

These were the worst earthquakes in Carinthia

Over the past 14,000 years, 44 earthquakes have been recorded at the bottom of Lake Wörthersee. Geologists have discovered this on the basis of samples taken from the lake bed. But what damage was caused by one of the largest earthquakes in Carinthia to date?

One of the largest earthquakes, which was recorded in Carinthia in 1348, was enormous in scale. Part of Villach's local mountain, the Dobratsch, collapsed as a result. The Gailtal valley was cut off and the Gail eventually dammed up to form a lake. Fortunately, earthquakes of such intensity are rather rare nowadays. There were tremors of this kind 11,500 years ago, at the end of the Ice Age.

In recent years, 130 drill cores in Plexiglas tubes up to 13 meters long have been taken from various Carinthian lakes from floating platforms. This is because traces of earthquakes in the form of sediments and landslides are preserved at the bottom of the lakes. However, the aforementioned earthquake in 1348, which had a magnitude of 6.9-7 on the Richter scale, is still under discussion: "Whether the origin, i.e. the epicenter, took place in Austria or in Italy has not yet been clarified," explained geologist and project participant Christoph Daxer, adding that it should be assumed that Austria was the epicenter.

What intensity was recorded at Lake Wörthersee?
According to the European Macroseismic Scale, an intensity of 8.5 was recorded at Lake Wörthersee, indicating that the earthquake in 1348 caused the strongest tremors in the Carinthian region since the end of the last glacial period. 

"According to our data, the probability of an earthquake of intensity level 7 or higher on the European Macroseismic Scale - in this case at least with cracks in the walls - is 5-6 percent in the next fifty years."

äußert sich Geologe Jasper Moernaut.

Cracks in Lake Klopein?
Data taken by geologists from Lake Klopeiner See is also currently being processed. "This appears to be quite poor in sediment, as it has very few inflows," explains Daxer. Deposits from the last 12,000 years are only two meters thick, which means that with a drill core of 13 meters, it is possible to look 17,000 years into the past. Much further than can be seen in Lake Wörthersee or Lake Millstätter See, for example.