The structure and geomorphology of the Dashgil mud volcano, Azerbaijan

The large-scale and small-scale (<10 m) structure and geomorphology of the active Dashgil mud volcano in central Azerbaijan, have been studied. Through historical records it is known that this mud volcano has major eruptions every 6-32 years. The activity observed during two field trips in 1995, consisted of low-energy venting and debouching of mud, water, oil, and gas from three mud pools (salses) and about 20 individual cones (gryphons) located on the summit plateau of the mud volcano. Besides the bubbling mud pools, ranging from 30 to 75 m across, and the cones, ranging from 0.8 to 3 m height, a 200-m-long string of about 10 sinter mounds was found on the summit plateau. The internal structure of the mud volcano and the processes responsible for the observed Dashgil geomorphology are discussed. Assuming the Dashgil mud volcano to be continuously active, with an average methane production similar to that observed in 1995, between the rare major eruptions, we have conservatively estimated the Dashgil mud volcano to produce an annual amount of at least 800 Sm-3 (standard cubic metres) of gas, mainly methane, which is emitted directly into the atmosphere. This estimate indicates that the natural contribution of atmospheric 'greenhouse' (radiatively active) gases from the world's terrestrial and submarine mud volcanoes is highly significant. (C) 1997 Elsevier Science B.V.