Geysers are a rare and spectacular geological event, representing a natural plumbing system that intermittently discharges a turbulent column of hot water and steam. They are a specific type of hot spring found only in a handful of locations worldwide where a precise combination of subsurface conditions exists. The scarcity of these features means the total global count remains an estimate rather than a fixed number, complicated by their temporary nature and the difficulty in classifying all hydrothermal activity.
The Current Estimate of Global Geysers
The generally accepted number of geysers worldwide is approximately 1,000, though this figure fluctuates based on current activity. This total includes all features documented as erupting geysers in modern times, including those that may be temporarily dormant. Of this thousand, around 500 to 700 are typically counted as active in any given year. The global distribution of these features is highly concentrated. Sources indicate that between half and two-thirds of the world’s geysers are located in just one area, underscoring the unusual combination of conditions required for their formation.
Geological Requirements for Geyser Formation
Geysers are rare because their formation requires the perfect alignment of three specific geological conditions. Primary is a powerful heat source, usually from a shallow magma chamber close to the Earth’s surface. This heat warms the groundwater to extremely high temperatures, often exceeding the surface boiling point due to immense pressure deep underground.
Another necessary condition is a continuous source of surface water, such as snowmelt or rainfall, which seeps down through the ground. This water travels to depths of up to 6,600 feet (2,000 meters) where it contacts the hot rocks. Finally, a complex plumbing system is needed, consisting of a network of narrow fissures, cracks, and tubes within a layer of silica-rich rock, often called geyserite.
This intricate subsurface structure differentiates a geyser from a non-erupting hot spring. The narrow channels prevent the superheated water from convecting and cooling, allowing pressure to build up until the water flashes into steam. The rapid expansion of steam then violently forces the overlying column of water out of the vent, creating the eruption.
Primary Global Locations and Concentrations
Yellowstone National Park in the United States is home to an estimated 300 to 500 geysers, representing more than half of the world’s total. The park’s unique position over a supervolcano caldera provides the necessary shallow magma heat source and extensive water supply. The park contains iconic geysers like Old Faithful and Steamboat Geyser, the world’s tallest active geyser.
Outside of Yellowstone, the remaining geysers are distributed across four other major fields globally:
- The Valley of Geysers on Russia’s Kamchatka Peninsula, home to over 90 geysers.
- El Tatio in Chile, the third-largest field, boasting over 80 geysers high in the Andes mountains.
- The Taupō Volcanic Zone in New Zealand, including the Whakarewarewa geothermal area.
- The Haukadalur valley in Iceland, home to the geyser after which all others are named.
Why the Total Geyser Count Varies
The difficulty in establishing a precise and fixed number for the world’s geysers stems from their inherently dynamic nature. Geysers are temporary features, and their activity can change dramatically. A feature must be a true intermittent erupting hot spring to be classified as a geyser, but activity can slow down, causing it to become temporarily dormant for years or even centuries.
The total count is also affected by human impact, which can permanently alter the delicate subsurface balance required for eruptions. Geothermal energy extraction or the drilling of nearby water wells can reduce the underground water pressure or temperature, causing geysers to cease functioning entirely. Natural events such as earthquakes or landslides can also clog or reroute the internal plumbing system, causing a geyser to become extinct or for a new one to form suddenly.