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I'm not a geophysicist but it doesn't seem like impermeable rock would "inflate like a balloon" and even if it did, that seems like it would be a pretty bad thing for the surrounding countryside. Given that water infamously doesn't like to compress, I'm at a loss for how this thing actually works.

Does anyone have a better explanation than this article?

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If you pressurize something "incompressible" like water under a cap of impermeable rock you are to still compressing the water and compressing the surrounding rock. The whole industry of fracking operates on compression rock to the point of fracturing it and forcing open the cracks. At 600-1300 bar water compresses 3-6%. It's the "equivalent" of a reservoir at the height of everest or higher.

I found "inflate like a balloon" a bit confusing/misleading. it's more like the fracture in the rocks expands(slightly) due to the pumping of water- and when the pump is turned off, the fracture goes back to a normal position pushing the hot water up. I am not an expert but I am really bamboozled by the reliability of this bc I imagine the rock/fracture will have to give away after some time(permanent rupture) or they will have to keep expanding the fracture.

It's a crack, not a void or a cave. The crack doesn't actually have significant volume (it probably does but all things considered it's tiny). It's like the space between two stacked bricks. Or maybe it's some permeable material like brick then sand then brick. You pump that full of water and you're basically lifting the bricks with hydraulic pressure. Gravity is what squeezes it back out.

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