Massive craters which were spotted in Siberia earlier this year by a television crew have left scientists pondering the mysterious phenomenon.
The craters measure to be about 30 metres deep and 20 metres wide along the Siberian tundra and it is at least the ninth hole to appear in the region since 2013, CNN reported.
Scientists believe the craters could be formed by a build up of methane gas exploding and creating the peculiar landmarks, although researchers are still unsure.
Evgeny Chuvilin is a lead researcher at the Skolkovo Institute of Science and Technology's Center for Hydrocarbon Recovery, and since the latest crater was discovered, he has been to the site to study it.
He told CNN as of right now, there was “no single accepted theory” as to why or how the craters were formed, though he said it was possible the crater had been forming for years.
The new crater was spotted by a crew affiliated with Vesti Yamal TV which was flying above on their way to an unrelated assignment, the Siberian Times reported.
According to the paper, Professor Vasily Bogoyavlensky, of the Russian Oil and Gas Research Institute in Moscow, human activities such as drilling for gas on the Yamal reserves could be responsible for the craters.
The Siberian runs across the north coast of the Russian region which has seen soaring temperatures of late, resulting in an acceleration in the melting of the Arctic permafrost.
Record-high temperatures were recorded in the region this year and nearly 300 wildfires swept across Siberia in July.
Scientists are now examining the craters, though they have to act fast as usually they turn into lakes, relatively quickly after they form.
“The main issue with these craters is how incredibly fast, geologically, they form and how short-lived they are before they turn into lakes,” Mr Chuvilin told CNN.
“Finding one in the remote Arctic is always a stroke of luck for scientists.”
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