"Local folks ignite these vents by throwing burning rags into them," Tingay wrote in response to one Reddit user asking about the flames. "Mud volcanoes usually don't have anything to do with regular volcanoes, which eject molten rock and hot gases. Some mud volcanoes are linked to hot geothermal activity, like those in Yellowstone National Park. However, Wandan's mud volcano is the more common type of this geological feature. "These mud volcanoes in Taiwan are driven by high fluid pressures that can form deep underground, rather than by magmatic influence," Tingay wrote in another Reddit comment.