A mud volcano erupted on an island in the Caspian Sea about 46 miles off the coast of Azerbaijan’s capital Baku on July 4, generating a blaze that lit up the night sky and took social media by a storm.
The eruption began at 9:51 p.m. local time (GMT+4) and lasted for eight minutes, says Gurban Yetirmishli, a seismologist at the Azerbaijan National Academy of Sciences, to Chingiz Safarli of the Trend News Agency in Azerbaijan. There are currently no reported injuries or fatalities related to the blast.
Initial reports speculated that an explosion happened at a nearby oil platform, but the State Oil Company (SOCAR) quickly debunked these claims, confirming no equipment was damaged, reports the Azeri-Press Agency (APA).
Mud volcanoes aren’t like typical volcanoes that spew molten rock or magma from the mantle. If classic volcanoes vomit the Earth’s churning guts, then mud volcanoes are more like a burp. Pressure from underground hydrocarbon gases builds up, and eventually, the gases force their way to the surface. On their way up and out, these gases may mix with water and react with mineral deposits to create a muddy slurry. The Caspian Sea is rich with oil and gas fields, which makes it a hotspot for mud volcanoes. In fact, this area has the world’s densest distribution of mud volcanoes, with some 400 dotting both the land and sea.
Sunday’s mud volcano eruption occurred on Dashli Island, which itself was formed by a past eruption, Yetirmishli tells Trend. The core of the volcano is just shy of a mile in depth, he says. The flames towered an impressive 1,600 feet into the air.
“This is most likely due to the fact that the volcano did not erupt for a long time and accumulated a lot of energy,” says Orxan Abbasov, a geophysicist at the Azerbaijan National Academy of Sciences, to APA.
Mud volcanoes erupt naturally, but how they light up on fire is still debated among scientists. Colliding rocks kicked up during the eruption could create sparks and ignite the escaping gases, suggests geomechanicist Mark Tingay of the University of Adelaide, Australia, in a Twitter thread. Other scientists have said that the rapid change in pressures alone can also trigger an explosion, he explains.
Dashli Island’s fireball display is not typical of other mud volcanoes in the rest of the world and their daily routines. Mud volcanoes are generally not dangerous to people and occur far from city centers, writes Dylan Thuras for Atlas Obscura.
"Unlike other volcanoes, the temperature of a single mud volcano remains fairly steady. However, from mud volcano to another, temperatures can range from as high as [212 degrees Fahrenheit] to as low as [35 degrees Fahrenheit]," AccuWeather senior meteorologist Tyler Roys tells Mary Gilbert in an AccuWeather article. Lower temperature mud volcanoes have even been used as mud spas.
The recent eruption isn’t Dashli Island’s first. According to Tingay, the volcano also experienced major eruptions in 1920 and 1945. Given Azerbaijan’s plentiful oil and gas reserves, more fiery blasts are likely to continue in the region.