Subsidence from old coal mine a possible cause of latest mystery hole.
Destruction of trees by flames could see Batagai Depression ‘rapidly enlarge’ while remote local settlements also threatened.
Three man team probing the discovery is now 'missing in tundra', say Emergency Ministry officials.
After a month of warm, dry weather and wildfires, the huge crater nicknamed ‘Mouth of Hell’ is now under direct threat.
Startling new details emerge of the most mysterious of Siberia's newly created giant permafrost holes.
Giant holes created when pingos erupted after filling with gas.
Earth is moving as 'leaking methane gas due to global warming causes surface to bubble' in a new phenomenon.
Same phenomenon of discharge of gas hydrates 'led to crater formation in Russia and disappearance of ships in Atlantic'.
Bulging bumps in the Yamal and Gydan peninsulas believed to be caused by thawing permafrost releasing methane.