From BldgBlog. An unbelievable fifty foot drop in the land in 52 years.
Makes you wonder if geothermal energy on a mass basis, with its deliberate fracturing on the earth’s crust could possibly have a few teensy unintended consequences.
How geothermal works
The idea of the hot dry rock is to drill at least two wells and, again by similar techniques to oil and gas, to make fractures between the two wells so you can have a kind of heat exchanger. You pump cold water on one side, it goes through these fractures and comes up.
In earthquake zones, no less.