A hot spring is a spring whose water temperature is 5 to 6 degrees higher than the average temperature of the surrounding air. The hot spring is different from surface water in terms of the amount of minerals and salts, radioactive materials, hydrogen sulfide and carbon dioxide. This spring boils from the depths of the earth and opens its way to the surface of the earth through faults and cracks. Some of these springs appear as a result of volcanic activity. They are often seen by the river and the sea and sometimes on the slopes of the mountains.
The heat of the spa spring can come from the central heat of the deep earth or the chemical reaction of the surface layers of the earth. The springs that can be seen on the slopes of the mountains often have a volcanic origin. In addition to their therapeutic properties, hot springs create extraordinary landscapes around them due to the deposition of various minerals. In the plateau of Iran, these types of mineral springs are located in the Alborz, Zagros and Azerbaijan mountains.
