>Iceland does quite well by it. Growing bananas in greenhouses inside the
>Arctic circle using the waste heat from their geothermal power plants.
>The crust is very thin there and in some places edges of natural lakes boil.
>
>One hazard when drilling boreholes for geothermal is unexpected
>breakthrough into molten magma. The titanium deflectors don't look too
>good afterwards but seem to control things. Magma is a lot less
>forgiving than oil if it escapes up the borehole.
Below Iceland, there are some huge pockets of hot water heated by the magma below during millions of years.
Drilling a bore hole into a pocket will return hot water or steam for decades or a century, but not forever.
The risk of hitting some active lava is quite low.