When the Vikings explored Iceland they made a settlement near an area of high geothermic activity. They called this village Geysir. The name of the village was given to the nearby geographical phenomenon of huge spurting steaming hot jets of water that regularly explode from the earths surface.
We now call them geysers. Old Faithfull in Yellowstone national park maybe the most famous geyser in the world but the ones in Iceland at Geysir are much taller and there are more of them. It is a fantastic place to visit.
Geysers are fountains of super heated water that explode at regular intervals through a vent in the Earth's surface. They are caused by water seeping through cracks in the ground rock coming into contact with volcanic magma. The intense heat boils the water, which then turns into steam.
his increases the pressure inside the crevice as bubbles of steam build up. When the pressure becomes too strong it expands up to the surface at very fast speeds through natural vents. The water is forced high into the air. When the jet has died down, the crevice fills with new water and the process repeats. When the volcanic heat dies down some geysers gradually lose their power and stop erupting. Other geyser just increase in the time between eruptions.