It is in the vast blue of the Caspian Sea that NASA satellites have documented a very intriguing geological event. At the start of 2023, a new land emerged from the waves, the result of the whims of an underwater mud volcano, before gradually disappearing from nautical charts at the end of 2024. How is this possible?
The mysterious cycles of Kumani Bank
About 25 km from the eastern coast of Azerbaijan lies Kumani Bank, also known as Chigil-Deniz, a mud volcano with an eruptive history dating back to 1861. Unlike conventional volcanoes which expel lava in fusion, mud volcanoes are the result of intense pressure exerted on water-saturated sediments in the deep layers of the seabed. Under the effect of this pressure, these sediments are propelled towards the surface, creating temporary geological structures.
NASA’s Landsat 8 and 9 satellites accurately mapped the life cycle of its last period of activity. In November 2022, the summit of the volcano still remained below the sea surface. Then, between January 30 and February 4, 2023, as analyzed by Professor Mark Tingay from the University of Adelaide, an island approximately 400 meters in diameter emerged from the waves.
This formation was accompanied by a sediment plume, a characteristic signature of the expulsion of muddy materials under pressure. Satellite observation then revealed the slow erosion of this ephemeral structure until its virtual disappearance at the end of 2024.
Azerbaijan, land of mud volcanoes
The exceptional concentration of mud volcanoes in Azerbaijan makes this region a unique place to study them. More than 300 training courses of this type have been identified in the eastern part of the country and off its coast, in the Caspian Sea. This particularity is explained by the geographical position of the territory, located in a convergence zone between the Arabian and Eurasian tectonic plates.
Historical records document several “ appearances » from Kumani Bank. In May 1861, an eruption created a small island 87 meters in diameter, rising 3.5 meters above sea level, which evaporated into the waves early in 1862. The eruption more powerful, which occurred in 1950, gave rise to an island, much more imposing, 700 meters in diameter and culminating at 6 meters above sea level.
These geological manifestations, described as “ strange and wonderful » by Professor Tingay, paradoxically remain little studied despite their spectacular nature. That can be explained in several ways : difficult accessibility, ephemeral nature, sometimes excessive costs of geological studies and complexity of the phenomenon itself.
- In 2023, an underwater mud volcano in the Caspian Sea formed an ephemeral island that dissolved by the end of 2024.
- These temporary structures result from sediments pushed up by extreme pressures, creating unique, but fragile formations.
- Azerbaijan, with its high concentration of mud volcanoes, is a key region for understanding these still little-explored phenomena.
