The mud volcanoes were formed when the fault under Cishan fractured and water seeped beneath the ground and formed mud together with mudstone;the mud is sprayed out of the ground through cracks by high-pressure gas, forming the mud volcanoes. There are three cone mud volcanoes in this area, the highest of which reaches 3.5 meters, with a slope of 50 degrees – a classic mud volcano, and Taiwan's most developed mud volcano. It erupts every few seconds, and thick mud flows down from the cone, forming a leaf-shaped mudslide.