Scientists have discovered four new huge craters in the Yamal Peninsula in the north of Russia.

      According to preliminary estimates their formation may be possibly caused by the impact of underground gases.

      The gas version was prompted by the fact that one of the craters was found near a gas plant. However, experts intend to study this phenomenon more elaborately.

      In addition to four large craters the experts found dozens of small-sized craters in the same area. Thus, the scientists expect that the craters might appear more and more.