A geyser occurs when a hot spring erupts, hurling a column of water and steam high into the air. These springs are situated in regions which were formerly volcanic and which have retained considerable heat near the surface.
They usually have craters with well-like shafts penetrating into the earth. The water which gathers deep down in these shafts becomes heated until the lower part is changed into steam, the pressure of the steam steadily mounts to a point when it suddenly hurls the water above it into the air, sometimes to a height of over 100 feet.
The chief geyser districts are in Iceland (home of the Great Geyser), in the Yellowstone National Park, Wyoming, United States, and in New Zealand. For four years Waimangu in New Zealand, the greatest of all geysers, was capable of spouting jets up to 1,500 feet.
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