Xiao Youkeng Yangmingshan park is located in a volcanic fumaroles, located in the Seven Star Mountain in Shanxi, about 805 meters above sea level, is Qixingshan Trail trailhead.

Xiao Youkeng for the type of volcanic activity notch terrain, a year-round fumaroles emit sulfur gas and steam, the temperature is high. Because of its volcanic activity into after the termination of underground there are still residual heat, the residual heat of the gas heating under the ground, so that the ground below the vapor pressure accumulation, and finally, in some particular place, blasting craters near the ground or fault out, resulting in burst mouth, Xiao Youkeng is such a case, as formed after the volcanic terrain.Here you can enjoy a string of crystalline, needle, color is yellow, the beautiful crystalline sulfur, and listen to the mouth of the burst jet sound, to experience the situation after the volcanic activity.