Formation

1. Geysers normally consist of a small surface vent connected to underground reservoirs and hot rock heated by magma
2. Cool surface water seeps through the ground and begins to fill the geyser
3. The water at the bottom of the geyser begins to heat up, but the narrow vent prevents convection and the pressure of the cooler water on top prevents the hotter water from escaping so the water becomes superheated
4. Eventually, the water near the bottom boils and bubbles rise to the surface
5. Water splashing out reduces the pressure, allowing the superheated water to boil violently, causing the steam & water to spray out of the geyser vent