A geyser is a hot spring that intermittently sends up fountainlike jets of water and
steam into the air. One of the world’s most famous geysers is Old Faithful in
Yellowstone National Park (USA). It blows out a 130-foot column of hot water and steam
for up to five minutes every hour. But Yellowstone’s Steamboat Geyser can send jets of
water up to 380 feet, making it the highest in the world. However, it was once outdone
by New Zealand’s Waimangu Geyser, which once sent water to heights of 1,500 feet in 1904.
Usually found in areas of volcanic activity, geysers and hot springs develop when
groundwater trickles deep into the earth. There, it is heated by hot gases and rock, and
trapped before it can return to the surface. Pressure begins to build until it becomes
to great that a pillar of steaming water erupts through cracks.
Geysers get their name from a hot spring in southwestern Iceland. Its name is Geysir,
meaning “gusher” in Icelandic. When Norse settlers first arrived there in the Middle
Ages, it erupted three times a day, but stopped after a nearby volcano erupted in the
twentieth century. Most geysers, unlike Old Faithful, are irregular. Their eruptions
depend on changes in groundwater flow, surface pressure, and even the tides.
Geysers can also be used in beneficial ways. In Iceland, the Geysir helps heat the
capital city of Reykjavik. And at The Geysers, a place in northern California, steam is
trapped to generate electricity for a city of one million residents.