[jjk166]

[0] https://scienceandtechnology.jpl.nasa.gov/sites/default/file...

You wouldn't want to drill into the magma chamber to relieve pressure, instead you would drill next to the magma chamber to cool the rocks on the edge, shrinking the chamber. Every few decades after the chamber had shrunk, you'd drill a new set of boreholes closer. The expense would be substantial, but well within the range of major government projects, and if you use the heat for power generation you can recover some of that cost - indeed if you subsidize the initial logistical setup, the long term operation can likely be fiscally self sustaining.

[gonzo41]

And if you make a mistake....or cause an earthquake things could very quickly get away from you.

[senectus1]

hasn't the unintended consequences of FRACKING taught us anything?

you go poking fairly stable systems and they will become unstable for us fairly quickly and uncontrollably.