New explanation for Siberia’s mystery cratersCarolyn Ruppel, chief of the U.S. Geological Survey’s Gas Hydrates Project, told EarthSky this week (March 9, 2015) that an explosive release of methane is not a likely explanation for the craters.
She and other scientists are calling on a simpler explanation, related to mounds of earth-covered ice in the Arctic and subarctic known as pingos.
National Geographic reported on February 27:
A pingo is a plug of ice that forms near the surface over time and has a small mound or hill on top.
When an ice plug melts rapidly — as many have been, thanks to unseasonably warm temperatures in Siberia over the past year — it can cause part of the ground to collapse, forming a crater.