Azerbaijan has the most mud volcanoes of any country, spread broadly across the country. 350 of the 700 volcanoes of the world are in the Azerbaijani Republic. Local people call them “yanardagh”, “pilpila” (terrace), “gaynacha” and “bozdag” alongside its geographical name – mud volcanoes.

A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity. Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots.