A word of caution.
If you are not careful, you can replace the four tiles under the center of a geyser. If any of these four tiles are a terrain that can't support Heavy (aka those necessary to build a geothermal generator), you'll not be able to build on it and get the message "...generator requires terrain that supports: heavy".

Context:
Playing an ocean-lock, used this to turn all the normal terrain to deep water, except my 10x10 starting island. Then would utilize terraforming mods to allow me to expand my island by expending wood. Didn't realize it swapped the floor under the geyser, which you can't terraform due to the spot being occupied by the geyser. Making building any geo-gens impossible. Thought this was a bug of the terraforming mod not properly classifying terrain, but no, it was my own stupid fault.

Just trying to save people some headache.