Caspian Sea Explosion Sparks Controversy in Azerbaijan; Is It Due to Oil Facilities or Mud Volcano?

On July 4, 2021, a huge explosion occurred in the Caspian Sea about 30 kilometers off the shore. The blast, which sent plumes of black smoke and flames into the sky, happened in an area where Azerbaijan has extensive offshore oil and gas fields. Although no casualties were reported, the exact cause of this event is still being debated.

Speculations of an Oil Rig Explosion

The blast took about 6 miles (10 kilometers) from the Umid gas field, which is 45 miles (75 kilometers) off Azerbaijan's capital Baku coast. It was initially blamed on a gas leak from an underwater pipeline.

There were also speculations that the blaze was due to an oil rig or ship explosion, but Azerbaijan's Emergency Ministry quickly dismissed it. State oil company SOCAR reported a preliminary investigation which indicated that the explosion was due to a mud volcano.

SOCAR deputy head Ibrahim Ahmedov reported that the offshore platforms and industrial facilities under the control of SOCAR are working normally, and no accident has happened there. SOCAR also rejected the claim by Azerbaijan's Oil Workers' Rights Protection Committee that a fire had broken out at an explosion site at the Umid gas field.

Naturally Burning Mud Volcano

According to official statements, the cause of the blaze was the Dashly Island mud volcano, also known as Ignatiy Stone Bank. Similar blasts of flammable hydrocarbon gas took place on the uninhabited island in 1920 and 1945.

The country is known as the "Land of Fire" because it is home to subterranean oil and natural reserves. Even explorer Marco Polo reported the fires caused by the burning gas during his journey in the 13th century.

University of Adelaide adjunct associate professor Mark Tingay confirmed that the explosion could be due to a mud volcano. He also said that the blast's location fits with a mud volcano called Makarov Bank, which previously exploded in 1958.

Azerbaijan's Republican Seismological Center offered the same explanation. The Caspian Sea has high concentrations of mud volcanoes that release mud and flammable gas. A quarter of them are known to erupt violently, according to Tingay. He also said that the mud volcanoes in Azerbaijan are some of the world's biggest and most violent. Several large volcanoes erupt each year, many of which can have big fires.

Seismologist Gurban Yetirmishli also suggested that the fire indicates a mud volcano, which would not be a surprise since the region is home to hundreds of mud volcanoes. Of the estimated 1,000 mud volcanoes worldwide, 400 are in Azerbaijan.

Experts are still unsure why mud volcanoes ignite, but a likely theory is that the rocks propelled upwards during an explosion can knock against each other and cause a spark that lights gases.

Flammable gases such as methane are trapped in the sediments beneath the floor in these volcanoes. In high gas pressure, the mixture of gas and mud is pushed up, triggering localized mud eruptions on land and underwater.