Hot springs are one of the earth's many natural wonders, and they attract visitors to places like Yellowstone National Park--in fact, hot springs are the most common thermal feature in Yellowstone. Hot springs are also found elsewhere in the world, including Asia, New Zealand and Iceland.
Deep Heat and Pressure
As rain and snow fall and percolate through porous rock, water can run deep into the earth, where it may come into contact with rocks heated by a chamber of magma nearly 10,000 feet under the earth's surface. Water temperatures at that depth can rise well above boiling, even up to 400 degrees Fahrenheit. The superheated water stays in a liquid state from the extreme weight and pressure of overlying rock and water.
The superheated water deep in the earth is energized and less dense than the cooler, heavier water falling down around it. As the cooler water sinks, it creates convection currents that help to circulate the superheated water back towards the surface, where onlookers often see a steaming, sometimes bubbling pool of water. Hot springs have wider openings that allow the pressure to decrease slowly as the water rises to the surface, whereas geysers have a very narrow opening, creating a high-pressure release.
Hot springs are often made even more amazing by their brilliant colors. These photogenic pools are often a deep cerulean blue caused by the sunlight passing into the clear water. Blue wavelengths of light are most often scattered, thus blue is the predominant color seen in the pools. Also, the pools are often rimmed with a light-colored rock called "sinter" that is built up by the heated water, which contains large amounts of silica. The sinter creates a bold backdrop for the colors.
Article Written By Naomi Judd
Naomi M. Judd is a naturalist, artist and writer. Her work has been published in various literary journals, newspapers and websites. Judd holds a self-designed Bachelor of Arts in adventure writing from Plymouth State University and is earning a Master of Fine Arts in creative writing from the University of Southern Maine.