Hot Spring

A hot spring or a hydrothermal spring is a place where the warm or hot groundwater issues from ground on a regular basis for at least a predictable part of the year, and is significantly above the ambient ground temperature, which is usually around 55–57 °F or 13–14 °C in the eastern United States.

Sources Of Heat

The water issuing from a hot spring is just heated by geothermal heat, essentially heat from the Earth’s interior. In general, the temperature of rocks within the earth increases with depth. The rate of temperature that increases with depth is known as the geothermal gradient. If water percolates deeply enough into the crust, it would be heated as it comes into contact with hot rocks. The water from hot springs in not-volcanic areas is heated in this manner.

In volcanic zones such as Yellowstone National Park, the water may be heated by coming into contact with magma (molten rock). The high temperature gradient near magma might cause water to be heated enough that it boils or becomes superheated. If water becomes so hot that it builds steam pressure and erupts in a jet above the surface of the Earth, it is called a geyser; if the water only reaches the surface in the form of steam, it is called fumaroles; and if the water is mixed with mud and clay, it is called a mud pot. Note that the hot springs in volcanic areas are frequently at or near the boiling point. People have been seriously burned and even killed by accidentally or intentionally entering these springs.

Warm springs are sometimes the result of hot and cold springs mixing but they may also occur outside of geothermal areas, such as Warm Springs, Georgia (frequented for its therapeutic effects by polio-stricken U.S. President Franklin D. Roosevelt, who built the Little White House there).

Therapeutic Uses

Because the heated water can hold more dissolved solids, warm and especially hot springs also often have a very high mineral content, which contains everything from simple calcium to lithium, and even radium. Because of both the folklore and the proven medical value some of these springs have, they are often popular tourist destinations and locations for the rehabilitation clinics for those with disabilities.

The countries that are most famous for hot springs are Iceland, New Zealand and Ikaria-Greece. The onsen (a Japanese word for "hot spring") plays a notable role in Japanese culture and it is one of the most popular tourism industries there.

North American Hot Springs :

Throughout the western North America (including Alaska) there is thousands of hot springs, many of which were created between 20 and 45 million years ago as a result of the violent volcanic activity. They range in the size from tiniest seeps to near geysers from seeps like Fales Hot Ditch north of Bridgeport, California to subterranean lakes such as the one below Tonopah, Arizona that provides natural mineral waters to the seven or more hot spring spas that once operated in Tonopah. The ruins of two such spas are still visible.

Native Americans And Hot Springs :

In Tonopah and Arizona, it is probable that water flowed forth from the ground by itself for a few millennia. This led the Native Americans to name the area as Tonopah, meaning "Hot Water Under The Bush". Native Americans has revered the hot springs as a sacred healing place. Though there are no Indian ruins in the immediate vicinity of hot springs, the presence of grain grinding mortar holes, pottery shards, and other artifacts close by to the west are clear indications that nomadic hunter-gatherers have frequented the area for many years. Every major hot spring in North America as well as those in the South America has some record of use by Native Americans, some for over 10,000 years.

Additionally, hundreds of very high quality arrowheads have been found at or near existing springs in Tonopah, which indicates that Tonopah was a popular hunting ground. This abundance of artifacts is indicative of importance of the springs to prehistoric peoples.

The Native Americans always used these natural shrines in a state of complete nudity. If opposing tribes, even those at war, arrived at the same spring, all conflict ceased because they believed that they were walking on sacred ground. Conversations were in hushed tones or more often did not take place at all.

See Also:

v Onsen (Japanese Hot Springs)
v Thermae (Roman Hot Springs)