Yellowstone national park is situated mostly in the State of Wyoming in the United States of America. Almost half of the geothermal features and world’s two-thirds of geysers are concentrated in Yellowstone. The largest hot spring in the park, and one of the largest in the world, is Grand Prismatic Spring. Steamboat Geyser located in Yellowstone’s Norris Geyser Basin with its eruptions as high as 380 feet (116 meters) is the world’s highest geyser. In 2002, Steamboat erupted twice (April 26 and September 13); in 2003, three times (March 26, April 27, and October 22); and most recently in 2005, on May 23.
Hot spring is a vent or a place in the ground where hot ground water comes out on regular intervals for a predictable time period of a year with the temperature of the water significantly higher than the ground temperature.
Hot springs are formed if the earth’s surface cuts across a water table. Definition of a hot spring and its features depends on the water circulatory system of the underground channels, internal intensity of heat and the heat dilution that occurs by the influence of cool ground water presence on the surface.
When an eruption occurs, hot springs become geysers. Hot springs boil with occasional churn on encounters with underground gases. Water passes through the underground channels and in the process collects minerals present in the rocks and carry them to the surface. Silica is carried in the water if the water passes through volcanic rocks. As the water cools on the surface, silica forms terraces of geyserite around the spring. Calcium carbonate saturated water is seen if the water passes through limestone. Calcium carbonate forms travertine on crystallization. Brilliant colors are seen around the hot springs as different species of algae, minerals, rocks and bacteria form rims around the hot springs.
Geysers are hottest of the hot springs with eruptions of hot water with steam on a periodic basis through the vent on the surface of the earth. Geysers are found in areas of recent volcanic activity. Water seeps downward under the surface of the earth towards the regions with high temperatures due to activity or young solidification of hot magma. Geysers are also known as dying volcanoes as the activity is the last stage of activity of a volcanic eruption where the magma deep underneath the surface goes through the process of cooling and hardening. Water gets heated and moves upwards to the surface along the channels of fissures and cracks in the rocks. As the energy source of a geyser is steam, water gets further heated; steam is formed and ejected through a vent at the earth surface.
Geysers, fumaroles, hot springs, are natural thermal features. Geysers are rare as geysers require regular water supply, a source to provide the intense heat, and a natural plumbing system to ensure movement of steam and heated water upwards with a constriction and without loss of heat. In the absence of a regular water supply required for a geyser, the thermal feature is called a fumarole. In the absence of the natural plumbing system required for a geyser, the water simply flows to the surface as a pool known as hot springs.