The terms mud volcano or mud dome are used to refer to formations created by geo-exuded slurries (usually including water) and gases. There are several different geological processes which may cause the formation of mud volcanoes. Mud volcanoes are not true (igneous) volcanoes as they produce no lava. Any point at which over time, the earth continuously exudes a mud-like substance, may sometimes be referred to as a "mud volcano". 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.
The terms mud volcano or mud dome are used to refer to formations created by geo-exuded slurries (usually including water) and gases. There are several different geological processes which may cause the formation of mud volcanoes. Mud volcanoes are not true (igneous) volcanoes as they produce no lava. Any point at which over time, the earth continuously exudes a mud-like substance, may sometimes be referred to as a "mud volcano". 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.
There are many mud volcanoes in Iran: in Hormozgan province, Sistan and Baluchestan Province and Golestan Province.
Most mud volcanoes in SE Iran occur in close proximity to the sea along the coastal region of the Oman Sea. The mud volcanoes in SE Iran are of two types, hot and cold.
The hot mud volcanoes, associated with the Taftan and Bazman igneous volcanoes located some distance inland, are the aftermath of volcanic activity and the temperature of the extruded water and mud varies from 70 ° to 90 °C, much higher than the ambient temperature. The exuded gas is sulphurous and sulphur incrustation forms in their craters. Cold mud volcanoes are sedimentary-tectonic in origin and are entirely unconnected with the igneous activity with water and mud at the same or lower than ambient temperature. The exuded gas is mostly carbon dioxide and biological in origin.The Borborok and Pirgel mud volcanoes described here are of the cold, sedimentary-tectonic type. Amongst the twelve mud volcanoes in the province of Sistan and Balochistan, only the Pirgel mud volcano is located inland some 300 km from the coast in the mountains between Khaash and Bazmaan.
Most of the mud volcanoes possess one or more mud cones which rise several meters high above the ground. However, some mud volcanoes such as the Ayen, Sanad mir Suban and Kaashi do not have cones and are simply reservoirs containing water and mud with no topographic expression and cannot easily be distinguished from the adjoining ground.Variations in the erosion rates together with their size and thickness has developed new and spectacular land forms.