Source: http://siberiantimes.com/science/casestu...

Respected Moscow scientist Professor Vasily Bogoyavlensky has called for 'urgent' investigation of the new phenomenon amid safety fears.

Until now, only three large craters were known about in northern Russia with several scientific sources speculating last year 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, so causing the formation of these craters in Arctic regions. 

Two of the newly-discovered large craters - also known as funnels to scientists - have turned into lakes, revealed Professor Bogoyavlensky, deputy director of the Moscow-based Oil and Gas Research Institute, part of the Russian Academy of Sciences. 

Examination using satellite images has helped Russian experts understand that the craters are more widespread than was first realised, with one large hole surrounded by as many as 20 mini-craters, The Siberian Times can reveal.