Geysers are not permanent features of land surface. They are formed due to volcanic activities and thousands of them exists world wide. They are about 500 active geysers in Yellowstone National Park at Wyoming, USA. They are also spread all over the island of Iceland. They have been many geysers in New Zealand which have been destroyed due to human activity.
They are two types of geysers- fountain geysers and cone geysers.
Old faithful geyser
Surface water goes down to a depth of 2000m approximately. Due to the extreme heat below the earth's surface, the water turns into steam and pressure increases. This pressure makes the water eject through the vents or cracks on earth's surface.The white stone around the base of the geyser is from dissolved minerals in the water.
Castle Geyser, in Yellowstone National Park.
Although there are many places in the world where hot springs can be found, geysers are extremely rare, largely due to the three specific requirements for their formation.Some geysers stop erupting when the volcanic heat gradually dies down.It may also cease due to earthquake influences and human intervention.