'Here we see that the pingo erupts due to the gas which fills its core. It's a very interesting process, which we have never observed before'. Picture: Yamalo-Nenets Autonomous region governor's press-service

A new expedition to the craters in Yamal, in northern Russia, shows how they have rapidly altered since they were first noticed last year, but also indicates the possibility that not all the craters were formed in identical ways. The holes - first noticed last year - intrigued and perplexed scientists from around the world, initially provoking a number of explanations as to their cause, the most outlandish of which was that they were caused by stray missiles or even aliens from outer space.

Now the experts say the formation is something 'never observed' before, linked to warm weather in recent years. New pictures from the expedition are shown here, showing how one of the holes has rapidly filled with water in recent months.

The most famous crater - known to scientists as B-1 - was measured by echo-sounder this week and found to be over 60 metres deep, significantly more than previously thought. But the experts are surprised how quickly it filled with water after the melting of the winter snow cover.

The water is now only 10 metres from the rim of the hole, and the scientists are witnessing a lake being formed before their eyes.



B1 crater a year ago. Pictures: Vasily Bogoyavlensky

Professor Vasily Bogoyavlensky, who led the latest expedition, told The Siberian Times: 'I think that next year it will be full of water and it will turn completely into a lake; in 10-20 years it will be difficult to say what happened here. The parapet will be washed away with rains and melting snow, the banks will be covered with water.

'This large crater fills with water rather fast - in just two years, so we need to examine such objects quickly.'

The professor, deputy director of the Moscow-based Oil and Gas Research Institute, part of the Russian Academy of Sciences, said: 'We can now say more confidently about the process that led to the formation of the famous Yamal crater B-1. It was combination of a thermokarst (a form of pre-glacial topography) process and the migration of gases from the depth'.

It was also created from a pingo, he believes, something that experts initially doubted.

'It was a pingo or bulgunnyakh (mounds with an ice core common for Arctic and sub-Arctic regions), and then, due to the Earth’s heat flow this pingo starts to thaw and its half melted ice core is filled with gas that originates from the depth through cracks and faults in the ground.

'We know for sure that there is a fissure in the ground under this spot, probably even two intersecting faults - gullies around the spot confirm this. Through the cracks, natural gas got into the melting ice core, filled it and the pingo erupted. It was also heated by a stream of warmth coming from the bowels of the earth through the cracks.'

It is believed methane gas was largely responsible, though readings taken by the latest expedition showed no abnormal gas levels at the site.

The process is different than usual, because 'normally pingos thaw and collapse, forming the craters and then lakes which is quite a normal process.

'Here we see that the pingo erupts due to the gas which fills its core. It's a very interesting process, which we have never observed before'.



B1 crater, Yamal, filled with water almost up to it's rim. Pictures: Yamalo-Nenets Autonomous region governor's press-service

At least two other craters, B-3 and B-4 that have appeared in recent years - though were only spotted in 2014 and 2015 - are formed the same way, he believes.

'But another giant crater B-2, which is located 20 km north of B-1 and is now a lake 50 x 100 metres in size, differs from them significantly', said Professor Bogoyavlensky. This crater has small 'satellite' holes around the main one.

'We couldn't find a mouth (or throat) in it, though we used different types of echo-sounders. Still the mouth can be there, but filled with mud, preventing us from detecting it. We will try to do it using other equipment.'

His initial theory is that it was caused in a different way to the others. 'We need to conduct the further research. The preliminary theory can be that it is a combination of the process that was on B-1, and that of a mud volcano. Initially it was definitely a pingo too.

'We saw the hillock on the space images and now, when we managed to examine it, we saw the remains of the ice core - the walls of very clean and transparent ice.

'The presence of the small craters around the big one - we can see more than 30 of them - can also indicate that the mouth of this crater had side channels, so the structure of this object can be compared to a tree. Gases went through the channels, forming many small craters, but not a big one.

'The other option is that here the gas went not from the depth via the cracks in the ground, but it was gas hydrate located close to the surface.

'Anyway, it is very interesting phenomenon and we need to conduct further research.'







Aerial map of Yamal craters, followed by images of B1 and B2. Pictures: Vasily Bogoyavlensky

It was the first time scientists - or anyone - had seen crater B-2 up close. It was initially spotted from analysis of satellite images.

'We were quite impressed when we saw this lake and about 30 small craters with our own eyes. Of course it is different impression, not the same when we first arrived on B-1 (the most famous Yamal hole). When you see a crater of more than 40 metres depth, which can fit a multistory building... Still B-2 is quite shocking.'

As yet they have not been able to find possible channels and calculate its depth. 'It's size is about 100 x 50 metres, with the 30 or so small craters around it.'

Of the 'erupting pingo' process, he said: 'At the moment we don't see any reason for panic'.

Yet the phenomenon must be watched as gas and oil is extracted from such regions where eruptions may suddenly occur.

'Pingos are quite common in Arctic areas, the largest are in Canada with some of them in Tuktoyuktuk Peninsula reaching one to two km in diameter and up to one hundred metres in height. In the Russian Arctic we have many with an average size of one to two hundred metres in diameter and about ten to twenty metres in height. The process of 'degassing' is not a new phenomenon either.

'Recently this became more active and, as we see, it can combine with pingos which then erupt. We have to monitor these objects, especially given the fact that Yamal is being actively developed for energy exploitation.

'Last year we passed to officials the information about a big pingo near a gas pipeline, which even began to lift the pipe like a jack-screw.

'Still the officials have not yet taken any measures to move the pipe. But we will continue to research and inform on possible dangers to infrastructure.'



B-1 crater pictured in the autumn of 2014. Picture: Vladimir Pushkarev

He indicated more erupting pingos are likely, and emphasised the importance of rapid research when new craters are spotted.

The expedition was organized by the Yamal government, namely the governor Dmitry Kobylkin, with active support of the Russian Centre of Arctic Development headed by Vladimir Pushkarev and Russian Academy of Sciences represented by well known expert, deputy director of Oil and Gas Research Institute, Professor Vasily Bogoyavlensky. Vice-governor Alexander Mazharov was personally involved in the expedition.

When the Yamal hole first appeared, many odd theories were put forward to explain the phenomenon, including that the cause was stray missile or a meteorite.

A research team from the Trofimuk Petroleum-Gas Geology and Geophysics Institute suggested the craters could be linked to the Bermuda Triangle in that explosions under the Atlantic Ocean caused by high gas hydrate emissions are thought to explain part of the mystery of ships and aircraft disappearing.

Ironically the name Yamal means 'the end of the earth', the same description applied to the Bermuda Triangle, off the Florida coastline.