“In Russia, we have a lot of experience studying permafrost,” said Mr. Chuvilin, who graduated from the Department of Permafrost at Moscow State University, one of the few universities to have such a specialty.
From this icebox of the Arctic, bits or even whole frozen mammoths, musk ox, woolly rhinoceroses, prehistoric horses, wolves and other ancient beasts wash out from the banks of rivers. But Mr. Chuvilin said he found no animal parts In the debris field of frozen mud the explosions threw out.
The strata of perpetually frozen soil are usually a few hundreds of yards deep, but they go down almost a mile In some places In Siberia. Each summer, a portion near the surface, known as the active layer, thaws.
With warmer summers, the active layer is the deepening, potentially melting and weakening the ice over the gas deposits.
The gases causing the explosions, said Mr. Chuvilin, may have built up to their current pressure tens or hundreds of thousands of years ago as the organic components of the permafrost partially decayed, before freezing.
Another possibility is the that methane trapped In deeper layers of the permafrost In a crystalline, ice-like form known as methane hydrates is the reverting to its gaseous state, possibly because of effects of global warming. In this theory, rising pressure rather than thawing on the surface is the causing the gas pockets to burst.