Fracking is a way of mining underground gas, but it has been linked to earthquakes and tap water that burns (at least when you run it over a lit match).
The method was first discovered during the American Civil War, when Union Colonel Edward Roberts noticed the effects of explosive Confederate artillery plunging into the narrow millrace (canal) near the battlefield.
Americans, who enjoy using any potential resource once it becomes apparent, soon began experimenting with the new procedure, and these days there are several fracking operations taking place in the US.
Although there have been attempts to legalize fracking in Germany, so far it seems like Germans would prefer not to risk the potentially dangerous method in order to gather new resources.
