Strange Sounds –
Reindeer herders in Russia’s Far North have discovered yet another mysterious giant hole about 30 kilometers away from a similar one found days earlier.
Located in the permafrost of the subarctic Siberian region of Yamal, which means “end of the earth” in the local Nenets language, both craters appear to have been formed in recent years and have icy lakes at their bases. . .
Strange Sounds mentions this – Third giant hole: The Crater of Nosok
Here is a picture of a LAVA TUBE … but investigating scientists would already know about those.
UPDATE, Aug. 22
Washington Post – Scientists may have cracked the giant Siberian crater mystery
“It may be methane gas, released by the thawing of frozen ground.”