A mission this week to the newly-formed crater on the Yamal Peninsula in northern Siberia is expected throw fresh light on how this and other such phenomenon were formed. Experts are working on a theory that gas hydrates caused underground explosions in the same way as eruptions under the Atlantic Ocean may have led to the Bermuda Triangle phenomenon.
Our new pictures show how, for the first time, scientists used climbing equipment to reach the base of the crater - a lake at least 10.5 metres deep with a frozen surface.
Leader of the new mission, Vladimir Pushkarev, director of the Russian Centre of Arctic Exploration, told The Siberian Times: 'We managed to go down into the funnel, all was successful. We used climbing equipment, and it is easier to do this in winter, than in summer, with the ground now hard.
'We took all the probes we planned, and made measurements. Now scientists need time to process all the data and only then can they draw conclusions.'
The funnel of the crater is about 16.5 metres deep, not including an earthen rampart on the surface, formed in the blowout, of several metres in height.
At the base is a frozen lake. 'The depth of the mini-lake is about 10.5 metres but it can be deeper. We are waiting for the exact information from readings taken by the scientists', Vladimir Pushkarev said.
The research to the largest of three known holes - all recently formed - in northern Siberia was initiated by the Russian Centre of Arctic Exploration, and included experts from a number of institutes. 'They did radiolocation tests at a depth of 200 metres, took probes of ice, ground, gases, and air. Now they all went back to their institutes and labs and will work on the material. The next stage is processing of the gathered information.
'Then we plan to explore the surrounding area, comparing images from space, and even those taken in the 1980s, to understand if there are - or were - some similar objects'.
It is possible other such phenomenon existed but were not noticed earlier.
Mr Pushkarev claimed it is too early to draw conclusions on theories on the crater's formation, including the suggestion from Russian scientist Igor Yeltsov, the deputy head of the Trofimuk Institute, that heating from above the surface due to unusually warm climatic conditions, and from below, due to geological fault lines, led to a huge release of gas hydrates, causing the eruption.
When the crater was first highlighted, earlier this year, it stoked many different theories including a manmade hoax, the work of aliens from outer space, a meteorite or even a stray missile. These are now discounted.
'I've heard about this Bermuda Triangle idea, but I repeat, our scientists need to work on materials first and only then draw some definite conclusions. At the moment we don't have enough information,' said Mr Pushkarev, a climber, rescuer and explorer who led the experts to the scene in temperatures of minus 11C.
'We haven't worked with other funnels yet. We plan to do this, but first of all we need to understand completely the nature of this very funnel to be able to create a model which then we'll use to compare with other craters'.