GC: n

CT: A geyser is a vent in Earth’s surface that periodically ejects a column of hot water and steam. Even a small geyser is an amazing phenomenon; however some geysers have eruptions that blast thousands of gallons of boiling hot water up to a few hundred feet in the air.
Old Faithful is the world’s best known geyser. It is located in Yellowstone National Park (USA). Old Faithful erupts every 60 to 90 minutes and blasts a few thousand gallons of boiling hot water between 100 and 200 feet into the air.

S: http://geology.com/articles/geyser.shtml (last access: 21 December 2014)

N: 1. 1780, from Icelandic Geysir, name of a hot spring in the valley of Haukadal, literally “the gusher,” from Old Norse geysa “to gush,” from Proto-Germanic gausjan, from PIE gheus-, from root gheu- “to pour”.
2. Intermittent thermal spring which throws up a column of hot water.
3. Geysers are extremely rare features. They occur only where there is a coincidence of unusual conditions. Worldwide there are only about 1000 geysers and most of those are located in Yellowstone National Park (USA).
4. Most of the world’s geysers occur in just five countries: 1) the United States, 2) Russia, 3) Chile, 4) New Zealand and 5) Iceland. All of these locations are where there is geologically recent volcanic activity and a source of hot rock below.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=geyser&searchmode=none (last access: 21 December 2014). 2. GDT. 3 & 4. http://geology.com/articles/geyser.shtml (last access: 21 December 2014).

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CR: fumarole , geothermal energy.