Unlike a traditional volcano, which spews molten lava, ash, and gases, mud volcanoes are geological formations that eject mud, water, and natural gas. This happens at a much lower temperature than a lava volcano. The process begins deep underground, where vast natural gas reserves are present. The gas, under high pressure, mixes with water and mud deep within the Earth's crust. The pressure forces this mixture to the surface through geological faults.
Once at the surface, the gas escapes, causing the mud to bubble and erupt. Sometimes, the mud and gas emissions are so powerful that a small eruption occurs, spewing mud several meters into the air. The mud that flows from the volcanoes dries and forms small, cone-shaped mounds that give the volcanoes their characteristic appearance.