Mud volcano

A mud volcano is a landform built by the eruption of mud, water, gases and slurries rather than molten rock, driven by pressure from hot subterranean water and gas forcing material up through faults and fissures rather than by magma. The vented material is mostly fine sediment suspended in water, carrying salts, acids and hydrocarbons, and roughly 86 percent of the gas released is methane. About 1,100 mud volcanoes have been catalogued on land and in shallow water, though scientists estimate more than 10,000 exist worldwide, mostly on continental slopes and abyssal plains, with notable concentrations in Azerbaijan, nearly 400 of them, and in the Makran range shared by Iran and Pakistan.