The term mud volcano or mud dome are used to refer to formations created by geo-excreted liquids and gases, although there are several different processes which may cause such activity. Hot water mixes with mud and surface deposits. Mud volcanoes are associated with subduction zones and about 700 have been identified. Temperatures are much cooler in these processes than found atigneous volcanoes. The largest mud volcano structures are 10 kilometres (6 mi) in diameter and reach 700 metres (2,300 ft) in height.
About 86% of the gas released from these structures is methane, with much less carbon dioxide and nitrogen emitted. Ejected materials are often a slurry of fine solids suspended in liquids which may include water, which is frequently acidic or salty, and hydrocarbon fluids.
Possible mud volcanoes have been identified on Mars.In Pakistan there are more than 80 active mud volcanoes in Balochistan province; there are about 10 locations having clusters of mud volcanoes. In the west, in Gwadar District, the mud volcanoes are very small and mostly sit in the south of Jabal-e-Mehdi toward Sur Bandar. Many more exist in the north-east of Ormara. The remainder are in Lasbela District and are scattered between south of Gorangatti on Koh Hinglaj to Koh Kuk in the North of Miani Hor in the Hangol Valley. In this region, the heights of mud volcanoes range between 800 to 1,550 feet (243.8 to 472.4 m).The most famous is Chandaragup. The biggest crater found at 25°33’13.63″N. 65°44’09.66″E is about 450 feet (137.16 m) in diameter. Most mud volcanoes in this region are situated in out-of-reach areas having very difficult terrain. Dormant mud volcanoes stand like columns of mud in many other areas.