Old Faithful Geyser

How geysers work

Geysers are generally located on the edges of the Earth’s tectonic plates. These plates are unstable, generating tremendous energy that erupt at fault lines. This dynamic can result in earthquakes and volcanoes; it also provides heat sources for geysers and hot springs. Geysers require water, heat, and a plumbing system. Many geysers are located near rivers and draw water from them. The water in geysers is heated by magma that lies around 3 miles (4.8 km) beneath the surface of the Earth.


The process occurs as water filters down to the geyser’s plumbing system through fissures in the ground and is under extreme pressure. As the magma at the base of the geyser transfers heat throughout the system, more energy gets trapped in the water. Eventually, as the water heats up, it becomes turbulent. This turbulence pushes water out of the geyser, releasing pressure. The water converts to steam. The steam quickly expands to 1,500 times the volume of water and which forces water and steam from the geyser. These eruptions continue as long as the water in the geyser remains hot enough to push water out. This continues until the system runs out of water or the water cools sufficiently to cease the process (or eruption). Then the cycle starts all over again.

Under normal conditions, the water, the heat and the underground structure all remain constant and for this reason Old Faithful erupts regularly. Conditions which cause deviations from the normal pattern seem to relate to earthquakes. The Old Faithful Geyser of California is proving itself a predictor of quakes.