A seismically active fault system runs deep under the Vienna Basin geological area, which covers Vienna, Lower Austria and parts of Slovakia and the Czech Republic.
Because many of the fault lines have been inactive for the last 200 or 300 years they are not thought to be hazardous.
However, geologist Dr. Kurt Decker from the University of Vienna told The Local that the risk of a large-scale earthquake occurring in the Vienna region has been underestimated and that scientists must examine historical data more closely.
“Earthquake records have only existed since around 1900, and therefore do not date far enough back to be able to make accurate predictions.
Of course such strong earthquakes are extremely rare but we need to examine data over a longer time period, we’re talking about thousands of years,” he said.
“There are half a dozen known fault lines under the Vienna Basin which are moving at a very slow rate, but we believe that every 20,000 years or so they are capable of causing an earthquake on the scale of 6.0 or 7.0 on the Richter scale,” he added.
The devastating Haiti earthquake of 2010 had a magnitude of 7.0, and affected an estimated three million people. “An earthquake of this scale in the Vienna region could have a catastrophic social and economic impact,” Decker said. “This is the seat of government and the most densely populated area in Austria.”
The Neulengbach earthquake of 1590 is the strongest historically documented earthquake in north eastern Austria, and it is estimated to have measured at 5.5 – 6.0 on the Richter scale.
A 2007 study by the reinsurance company Munich Re estimated a damage potential of between €10 billion and €15 billion to private property in Vienna alone should an earthquake comparable to Neulengbach ever happen again.
Decker and his team have been gathering data on one of the fault lines under the Vienna Basin, using geological techniques to examine sediment layers left in the landscape after an earthquake which allow them to date the quake and get an estimate of its magnitude.