Tuesday, May 1, 2018

Earthquakes

Due to the Rhine valley fault, Germany‘s southwest is a region of frequent but minor seismic activity.


The strong earthquake in Basel of 1356 was an exception, although its impact was not as severe as the famous one in Lisbon of 1755. Strangely, Freiburg has no testimony about the Basel earthquake. Shock waves certainly must have been felt. On the contrary, the generous help Freiburgers gave to the people of Basel afterward is well documented.

Exaggerated damage in the Basler Chronik of 1580 by Christian Wurstisen
A cut through the Rhine valley shows from left to right the granite Vosges, the tectonic faults covered by sediments in the valley, the volcanic cone of the Kaiserstuhl, and the uplift of the Black Forest gneiss. All these distortions lead to unrest in the underground.



The combined lecture by Drs. Brüstle and Braumann: Earthquakes in Baden-Württemberg from the Middle Ages to today. Historical research and seismological evaluations was hailed as a fruitful collaboration between science and humanities. No wonder the auditorium was overcrowded. Against my habit, I was late but luckily got the last seat in the first row.

While Braumann had dug up old written testimonies of seismic activities in the region, Brüstle had analyzed the events preparing and completing the input for a database with about 10,000 events over the last 1000 years. Braumann found 700 original documents about seismic events unknown so far.

Hand-written entry in the top margin of a Medieval Stundenbuch (a prayer book, also a book of hours)
 about an earthquake in Nördlingen on March 26, 1511

The hand-written Council minutes of Endingen in1728.
The report about the earthquake starts in the middle of the left page.

Semi-scientific approach to the recording of seismic activities.
Entering observations about St. Blasien on July 2, 1899, hand-written into printed forms. 
An abyss opened between humanities and science in the discussion following the presentation. People confused the measured frequency of earthquakes with their likelihood and, even worse, their predictability.

We need more STEM education now!
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