by :ng jing xiang (n.j.x)
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.
Conditions RequiredWhere are Geysers Found? 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. for a Geyser 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).

Conditions Required for Geysers
1) hot rocks below
2) an ample ground water source
3) a subsurface water reservoir
4) fissures to deliver water to the surface







What is a geyser?
A GEYSER IN ACTION. Located in Calistoga, Calif., this geyser also goes by the name Old Faithful.

Imagine yourself exploring a desolate, rocky region in Iceland or Yellowstone National Park, minding your own business and admiring the volcanic formations around you. The ground is relatively flat but covered in mounds of yellow and white material with a vague but distinctive smell of rotten eggs. The entire area is mysteriously foggy, framed by trails of vapor rising from cracks in the earth everywhere you look. Suddenly, steam and hot water burst out of the ground in a spectacular fountain that lasts for several minutes, reaching hundreds of feet in the air and making a roar like a freight train speeding right past you. Just as quickly as it began, though, the event ends, leaving small pools of steaming water in a wide circle around the vent.
What you would have witnessed is a geyser eruption, one of nature?s most impressive displays of hydrothermal energy. They occur where magma lies just below the earth?s surface, particularly in volcanic regions such as Iceland or New Zealand, and places that have been volcanically active in the past, including Yellowstone in Wyoming. Water from rain or melted snow percolates into the ground through cracks and fractures and interacts with the hot underlying rocks. The water reaches temperatures far above where it would boil on the earth?s surface (about 100 degrees Celsius), but because there is so much rock above the water (sometimes up to several miles), the water does not boil. Instead it becomes superheated and pressurized. Once enough pressure builds up, the superheated water will overcome the weight of the overlying rocks and burst out of the ground in an explosive steam eruption?a geyser. It basically works like a teapot with a closed lid; only when enough pressure builds up from accumulating hot water and steam is there enough force for the steam to burst out through the top and activate the whistle.