Geysers are one of those natural phenomena that everybody loves, but most people know little about them. What are they; why do they exist and, do they have anything to do with volcanoes? Read on and next time you see one of these shooting streams of water, you'll know all about it.
The English word 'geyser' comes from the Icelandic verb 'Geysa', which quite appropriately means 'to gush'. Geysers are found throughout the solar system, on Saturn's moon Enceladus and Neptune's moon Triton. There are around a thousand active geysers on Earth. These and divided into two main types:
The famous Yellowstone National Park in the United States houses the world's largest collection, containing over half the amount of active geysers in the entire world. While there are plenty of geyser-less volcanoes around, you may have noted that they tend to occur in volcanic regions. There is a reason for this, as geysers are similar to volcanoes in that they both depend on a high source of heat below the ground. However, the similarities end there.
Geysers occur, not only where there is a patch of heat below ground, but also where there is a flow of groundwater underneath the land. The groundwater seeps through cracks and fissures until it comes into contact with incredibly hot volcanic rocks. The rocks heat the water so much that, due to pressure buildup below the Earth's crust, it eventually explodes above the surface into a fantastic stream of boiling water and steam. This is a geyser, and what a magnificent sight it is! But then, as the boiling water converts into steam and the supply of scorching groundwater wanes, the fountain stops its spectacle.
However, geysers don't erupt only once, nor do they erupt randomly. Usually, more groundwater will find its way to the top of the very same underground heat source, and with time, it will boil as well. When it reaches the point where the ground can contain it no longer, it will shoot up in its classic water cannon style, once again thrilling onlookers. The timing is so regularly that some geysers even have a predictable schedule as to when they'll blow - hence the name of Yellowstone's most famous geyser, Old Faithful.
Old Faithful, though, is no longer as punctual as she used to be. As it turns out, geysers aren't necessarily immortal and changing environmental conditions can affect the frequency of their eruptions. Many of the geysers in Yellowstone are now erupting less often; Old Faithful, for instance, went from exploding every 15 minutes to every hour and a half from 1998 to 2006. Undoubtedly this is due to changes in the surrounding environment. Many scientists think that a drier climate could cause this while others see it as an ominous warning sign that the supervolcano lying below the park is getting ready to erupt!
Another example of geyser death was when a landslide changed the geologic landscape in New Zealand's Taupo Volcanic Zone, burying the Waimangu Geyser, once the largest known geyser on Earth. Geysers have also been killed off by careless tourists suffocating them with trash, so it is important to conserve the environment around these graceful giants so that the spectacle can spew on.
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