I recently just bought the game, and 2 rifts were right at a clay deposit where i just built a quick base, so i just decided to turn them off with commands because they were annoying as hell.
However, i believe that i disabled rifts (and maybe) monsters alltogether with this command, because i haven't seen a drifter or a rift in new worlds i made.
Now, the problem is that i can't find the command that i used anymore, and i believe it need to turn it back on via commands, because i checked the world customization before i created a new world, and it says that Rifts are on.