The theories posted on this video thread are from all over and who knows, maybe one of them is right:

One of the more far out comments states:

That’s because it’s a pocket of dark matter. the inside of the earth as dark matter in it just like galaxy do when galaxy collide the dark matter continues to fly away while the matter goes back together you’ve seen this on sixty symbols. The earth has dark matter inside of it but it is trapped, now the cern is the cause of these holes and also orbs floating away from the tops of mountains, also I think that it is the cause of gravity and anti gravity like + and – pressure on spacetime. Matter is + pressure and anti matter or dark matter is – pressure. Space compression and expansion through time

Another commenter had this to say:

if it was a sink hole, it wouldnt have blast debris around the outer edge. If it was a meteor, for the size of the hole, there would be more blast debris. This has come from below, and they are methane pockets being released and exploding out, releasing an invisible gas. This is happening all over Russia and Siberia, and is accelerating the global climate problem.

What do you think caused this?  Feel free to comment.