Every year, hundreds of tremors shake this German region, which was hit by an earthquake with a magnitude of 6.1 in 1911.
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It is a region in Germany where the earth shakes regularly. The southwest of the country, near the Rhine and Alsace, is considered the most earthquake-prone area in Germany. This region is definitely located in a plate collision region, but the part of the event remains unclear.
At the Friborg Seismology Center, tremors appear on a screen in the form of colored curves in almost real time. In 2023, 466 earthquakes have been recorded in this region. “We have earthquakes every dayStefan Stange, Head of the Seismology Department, explains. There, we see it last week, in red. There were six. It lasts two or three seconds, not more. Why they happen in these places, and not 20 kilometers away, we have no idea. Building regulations are stricter here because it is believed that stronger earthquakes may occur in the future.”
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A 5.4 magnitude earthquake in 2004
To better understand the phenomenon, 50 seismographs measure tremors in the region. Technician Ralf Ortlieb maintains equipment in the basement of a building in Freiburg. “These devices are very sensitivesays Ralph Ortlieb. For example, a wood saw can disrupt a measurement within a radius of two kilometers. We install them in quiet places, underground, graveyards or near water tanks, these are the best places.”
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99% of tremors are weak enough to be felt by the population. Others, stronger, left an impression. Dagmar remembers the earthquake in Waldkirch 2004, with a magnitude of 5.4 at 2:52 am “We were sleeping and suddenly we felt the house vibratingDagmar says. It felt like the rocks were sliding towards us. It scares us.”
“We didn’t know if we should go out or stay in. It’s happened twice since we’ve lived here in Waldkirch.”
After each earthquake, residents’ observations are collected at the Friborg Seismology Center. A valuable resource explains Andrea Brustal, who analyzes the data : “This is a short questionnaire on the Internet. You have to indicate the time, place and intensity of the sensation. There is a scale: did I feel it a little, or more strongly, what caused me to hit the glasses? This allows us to evaluate are.”
An earthquake with a magnitude of The region is expected to see a figure of 6.9 in October. But it will be an exercise, organized by the authorities to create awareness among the population. Real earthquakes are unpredictable by nature.
