Yellowstone and Hawai'i are among our favorite places -- and RCI's too, since they are designated as "hot locations". For geologists as well, they are well known "hot spots".
Two of the most famous, in fact -- where age old plumes of lava rising from the center of the earth penetrate the crust to make spectacular displays. The lava towers rising from the ocean floor at the Big Island have the greatest height from their base of any mountains in the world. And the lava intrusion under Yellowstone was enough to lift the mountains, cracking them as they buldged, so that water infiltration into the cracks has created geysers.
For a full scale version of shock and awe, consider the Yellowstone area of 600.000+ years ago when a gigantic explosion blew open a pit about 30x50 miles wide and thousands of feet deep. Earlier blasts in the Yellow area were thousands of times as powerful as Mt. St. Helens. Or reflect on the idea that the lava plumes are stationary, boring holes in the crust which drifts above them like lily pads on a pond (the theory of tectonic plates). I'm fully in tune with the psalmist who cried "When I consider the heavens . . . "
Geysers form when surface water percolates down to heated rocks below. The heated water rises, forming steam as it nears the surface. That steam powers the eruption of the geysers. "Geyser" is an Icelandic word meaning to "gush forth". As a last coincidence, consider the Hawaiian meaning of Waikiki -- it means "spouting water".