Yanar Dag is a natural gas fire which blazes continuously on a hillside on the Absheron Peninsula on the Caspian Sea near Baku, the capital of Azerbaijan, which itself is known as the "land of fire." Flames jet out into the air 3 metres (9.8 ft) from a thin, porous sandstone layer. However a visual comparison of the photos of Yanar Dag compared to images of mud volcanoes will show the difference between this seep and the "sedimentary volcanoes" or "gas oil volcanoes" concealed below land and sea in the Caspian region and which Azerbaijan has the largest concentration globally, though others exist in Turkey, Turkmenistan and elsewhere. Yanar Dag is also known by other names such as "pilpila", "bozdagh", "ahtarma" and "gaynarja." Unlike mud volcanoes, the Yanar Dag flame burns fairly steadily, as it is not a periodic eruption, but a steady seep of gas from the subsurface. It is also claimed that the Yanar Dag flame was only noted when accidentally lit by a shepherd in the 1950s. As noted in the photos, there is no seepage of mud or liquid from the seep, which distinguishes it from the nearby mud volcanoes of Lokbatan or Gobustan. The Yanar Dag fire is never extinguished. Around this open fireplace the atmosphere is filled with the smell of gas. The flames emanate from vents in sandstone formations and rise to a height of 10 metres (33 ft) (different figures are mentioned in other references) at the base of a 10-metre (33 ft)-wide scarp below a hillside. Yanar Dag is described by the Geological Survey of Azerbaijan as "Intensive flames, to 1 metre (3 ft 3 in) 3 in) high, develop for 15 metres (49 ft) along the base of a 2--4 metres (6 ft 7 in--13 ft 1 in) in--13 ft 1 in) high and 200 metres (660 ft) long tectonic scarp". The surface flames result from the steady gas emissions from underlying soils. Even on the surface of streams near Yanar Dag fire can be ignited with a lit match. These streams, which otherwise appear calm, are known as Yanar Bulaq -- "burning springs". There are several such springs in the vicinity of the Vilascay River, which the local people use to take a curative bath for their ailments. Alexandre Dumas, during one of his visits to the area, described a similar fire he saw in the region inside one of the Zoroastrian fire temples built around it. Only a handful of fire mountains exist today in the world, and most are located in Azerbaijan. Due to the large concentration of natural gas under the Absheron Peninsula, natural flames burned there throughout antiquity and were reported on by historical writers such as Marco Polo. The closest city to Yanar Dag is Baku, the capital of Azerbaijan, which has a good network of roads, railway lines and ports. The Heydar Aliyev International Airport is the nearest airport, which is 25 kilometres (16 mi) away from Baku (one km off the Baku-Mardakan road). Baku International Marine Trade Port in the Bay of Baku is the nearest port. Most mud volcanoes are located off the Baku‐Shamakha road, about 40 kilometres (25 mi) away from the city. The reasoning offered for the Yanar Dag fires is the result of hydrocarbon gases emanating from below the earth's surface. Apart from Yanar Dag, the most famous site of such a fire is the Zoroastrian Fire Temple near Baku, off the Greater Caucasus, which is a religious site known as ateshgahs, meaning temples of fire. It has also been inferred that such fires could be the cause for "thermal metamorphism". Like Yanar Dag, the Ateshgah is also a seep through porous zones, and not a mud volcano, such as those found at Gobustan or Lokbatan. According to the scientific study carried out by the scientists and geologists of the Geological Survey of Azerbaijan, from four samples taken from the Yanar Dag, the maximum flux was recorded at the upper side of the fault scarp from where the flames emanate. The value of microseepage recorded was 103 mg•m22•d21 at 30 metres (98 ft) from the fire, on the upper part of the study area. It has been inferred that the total degassing area is clearly larger than the measured area, and it is very likely that the microseepage is pervasive along the fault zone. This fault scarp is also inferred as a part of the huge Balakhan-Fatmai structure on the Absheron Peninsula. The naturally occurring fire burns in colourful flames most impressively at dusk, when both tourists and locals can view it from nearby teashops. The numerous links to fire in the folklore and icons of Azerbaijan are attributed to a connection to the ancient Iranian religion of Zoroastrianism, which first appeared in this region over 2,000 years ago. This created a cult of fire worshippers in Azerbaijan before the Islamic rule came into effect. Yanar Dag continues to inspire artists; in recent years through a Finnish opera and a French Canadian stage play.

• published: 16 Sep 2013
• views: 2