The ground rumbles beneath your feet. You hear a popping noise and a hissing sound. Suddenly, countless gallons of scalding hot water, along with pressurized steam, are propelled hundreds of feet into the air. What is the cause of this strange phenomenon?

Facts about Geysers

  • There are two main types of geyser: steam-driven and cold-water.
  • Steam geysers are caused when water deep beneath the Earth’s surface gets heated by hot magma and causes pressure to build up.
  • On large time scales, geysers are only temporary. There are a number of reasons why a geyser will form or go dormant.
  • Geysers exist on other planets and moons, too. On other planets, they spew chemical vapors, ice and dust.
  • The most famous geyser is Old Faithful, located in Yellowstone National Park, Wyoming, United States.
  • The world’s tallest geyser is Steamboat Geyser, Yellowstone.

What Are Geysers?

The word “geyser” means “to gush,” referring to the movement of steam and water when a geyser erupts. Geysers are underground reservoirs of water that intermittently eject water and steam. Fractures, cavities, and porous areas in the rock above act as “pipes” through which rain and water flow into the reservoirs. When enough pressure builds up in the reservoirs, they erupt.

Geysers don’t last forever. Earthquakes, human activity, the movement of tectonic plates, and other factors can cause a geyser to stop functioning. Even throwing garbage into a geyser may change its conditions enough for it to go dormant.

Why do most geysers spew out hot water?

Surface water from rain and rivers trickles down through the earth, reaching a depth of nearly 7,000 feet (2,000 meters). There, it comes into contact with rocks heated by molten magma deep below the earth’s surface. The water boils, creating pressure. The water and steam are pushed to the surface and erupt from a surface vent. This is called a hydrothermal explosion (hydro means “water,” and thermal means “heat”).

What are the types of geysers?

Geysers can be divided into two main types, steam-driven and cold-water.

Steam-driven geysers can be further be divided into two types – fountain and cone. Fountain geysers erupt from beneath pools of water, usually in short bursts of a few seconds each. Cone geysers, however, consist of mounds of minerals. Cone geysers may erupt continuously for several minutes. Some may erupt for more than an hour at a time.

The other main type is called a cold-water geyser. Instead of heat driving the water from the ground, carbon dioxide (CO2) collects in underground lakes called aquifers. The weight of the water contains the carbon dioxide bubbles until the rock layer above weakens and forms a fissure, or crack, or when humans drill through the rock. The bubbles then expand and propel the water upwards with great force. Only a few of this type of cold-water geyser exist, and they are located in the United States, Germany, Slovakia, and Brazil.

Are there geysers on other planets?

Geysers have been found on Mars and several moons of Jupiter, Saturn and Neptune. Huge eruptions of water vapor were detected on Saturn’s moon Enceladus by the Cassini satellite. The eruption plumes can contain water vapor, chemical vapors, ice and dust.

Scientists refer to these geysers as cryogeysers or cryovolcanoes (cryo meaning “icy cold), because of the low boiling point of the contents in the ejected material. Chemicals such as ammonia are mixed with water on the planetary body, lowering the freezing point of the mixture.

What are some famous Geysers?

Over one thousand geysers are active around the world. Being a relatively rare phenomenon, tourists often visit geysers to see the water spray high into the air. The following are a few of the most well known geysers.

  • Old Faithful. Perhaps the most famous geyser in the world, Old Faithful is a cone geyser located in Yellowstone National Park in the United States. This geyser is called old faithful because it is very predictable, with eruptions occurring every forty-four to one hundred and twenty-five minutes. Yellowstone National Park is home to more geysers than anywhere else in the world, with as many as five hundred active geysers observed each year.
  • Steamboat Geyser. Located in Yellowstone National Park not far from Old Faithful, the Steamboat Geyser is the tallest currently active geyser in the world. The Steamboat Geyser regularly expels water more than three hundred feet (90 meters) in the air. This geyser is dormant at times, with the length of time between eruptions ranging from a few days to more than fifty years.
  • The Great Geysir. Located in Iceland, this geyser was discovered during the 14th century. The word “geyser” is derived from its name. While this geyser is often dormant, it is induced to erupt on special occasions by the addition of certain chemicals.
  • Strokkur Geyser. Also located in Iceland, the Strokkur Geyser is known for erupting every five to eight minutes.
  • El Tatio. El Tatio is a field of eighty geysers located near active volcanoes of the Andes Mountains in Chile. El Tatio means “oven” in the local Quechua language, describing the geothermal heat. This area is known for its low geysers. Most of the geysers divulge water only to a height of thirty inches (750 millimeters), with the tallest reaching a height of twenty feet (6 meters).