[Earth Cache] 공식 1호점 어스캐시!!! Onyang Hot Spring Onyang Hot Spring A hot spring is a flow of water from underground that is heated by pressure of being underground and from the heat generated by the core of the planet. The water flows up the sulfur mountain thrust fault and emerges at the surface. At Onyang hot spring the temperature of the alkali water is at around 57C°/135°F. It has a high concentration of radium. Some of t..