GeyserA geyser is a hot spring which ejects hot water as vapors through a crack in the rock.  The formation of a geyser takes a very specific geology which is only found in a few places on Earth.  Geysers are found in areas which have volcanic activity.  Water from the land surface seeps into the groundwater and collects in pockets.  These pockets of undergroundwater are heated a by volcanic rocks over one mile below the land surface.  When the water begins to boil, the water and vapors are ejected from the geyser because of the great pressure caused by the heating.  The water and vapors escape through cracks in the rocks.

When the water begins to cool to a temperature below boiling, the eruption of the geyser ends.  Geysers can erupt from just a few seconds to several minutes.  Each geyser has a different length of eruption and a different amount of time between each eruption.  About half of the world’s geysers are located in Yellowstone National Part in the United States.  Geysers will erupt periodically over their lifespan of about several thousand years.  One of the most famous geysers is “Old Faithful” in Yellowstone National Park (shown in this photo).

One Response to “Geysers”

  1. This explanation of geysers gives some of the basic facts about these fascinating phenomena, and they really are great to watch. One thing that didn’t get mentioned is that part of the definition of a geyser is that it erupts periodically, with quiet times in between eruptions, whereas some hot springs erupt without stopping and are called perpetual spouters.

    You can even make a model geyser, and I know of some people who have entered them in science fairs. The organization called the Geyser Observation and Study Association studies geysers all over the world and has a Web site ( and a listserve where observations are shared.

    You can also see pictures of some of Yellowstone Park’s geysers and more information about them at the Web site listed here.

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