When you inject cold water into hot brittle rock, fracturing can occur.

You'll notice western Oklahoma is now replete with earthquakes, when they were never there before. From fracturing.

I liken this idea to defusing a bomb with a circular saw- sure, you might chip away at the explosives, reducing the yield when it goes off, but you also might short the detonator out and trigger an eruption.

Luckily, looks like the economics of this are prohibitive and likely to stay that way.