I just wanted to share with you an article I read in the German magazine Spiegel because I found it as spooky as fascinating. It is in German, so here is a rough and partial translation. For those of you who speak German, the full original article can be found at
and photos are here.
After Geothermal Drilling: A town rips up
Exemplary into disaster: The idea was to heat the town-hall in Staufen with geothermal energy. But briefly after the drilling the horror began. Everywhere in the town, cracks and crevices started to appear. Nobody knows what else is to expect - and who is to blame.
Staufen in Breisgau: A small, quiet town near the Black Forest. 7800 people live here, where the world is still all right. More precisely: Where the world was still all right. Then last fall, the disaster started to happen...
It started with a worthily idea. One wanted to heat the historical town hall with climate-friendly geothermal heat. An Austrian company was hired, seven drillings were made below the town-hall, 140 meters deep.
Briefly after this, the first cracks appeared in the historical building. At first one was not really worried. Mayor Michael Benitz spoke of “cosmetic damage”. “In the beginning the movement was in the millimeter range,” he says. But it didn't stay that way: Millimeters grew to centimeters, and the cosmetic damage grew to a catastrophe. These are at least the words Mayor Benitz uses when he talks about the uncanny events in his town.
The cracks in the town-hall began to grow, spread to the surrounding houses, and became longer and deeper. Like monster from inside the earth, they gnaw on the town. After only one year, more than a hundred houses show cracks. Sometimes they are so deep you can reach into them.
Something is going on below Staufen. The whole town has raised. And that on scales that are enormous in a geological context. We are talking about several centimeters per month.
What is going on?
Geologists were asked for advice. They should clarify if - and if so, how - the mysterious cracks were caused by the drilling. Scientists from the Technical University (TU) Darmstadt have a theory. Ingo Sass, geological engineer at the TU Darmstadt and expert for geothermal drilling, suspects [...] that the following happened: “One started drilling below the town-hall and broke through the gypsum-keuper-layer, under which there is groundwater under high pressure.”
Keuper is an anhydride, a calcium sulfat. In contact with water, if forms gypsum. And that gypsum expands. When the groundwater layer below the Keuper was drilled into, water rose through the drilling and came in contact with the anhydrite. This caused a chemical reaction. The volume growth in this process can be up to 60 percent. [For details, see e.g. this paper.]
The people in Staufen are desperate [...] Presently it is checked whether it is still save to enter the town-hall at all [...]
Sass further says: “This can go on like this for years, depending on how fast the water raises.” He is even afraid the worst is yet to come. The plaster could partly resolve again the water, causing hollow spaces below the city. “I can not exclude this situation won't become dangerous.” Because then, there could be sudden collapses. “Something needs to be done urgently,” Sass says. “The water contact needs to be stopped." But that will be expensive.
But as long as the question of responsibility is not clarified, no insurance company will pay. A report was alread conducted to bring clarity.
Geotechnicians took temperature profiles in the drilling holes and at 30 other places in the city center, and measured the vertical motion. In the end however, nothing could be said with clarity. The drilling might have caused the problem. Or maybe not. It could also have a natural cause.
“Staufen is a tectonically active area,” says Sass. “Of course it is possible that the layers moved tectonically against each other which changed the water flow and caused the reaction.” But: He doesn't consider this to be very probable.
That the start of the events coincides with the drilling is a strong indicator against natural causes. Why would this weird raise of the ground start now, so briefly after the drilling. Most of the inhabitants of Staufen do not believe in theoretically possible natural geological processes [...]