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Comment by mike collins

Re; cryoseism. I ain't buying the freezing groundshakes theory, here's why. In a severe temperature drop the ground is insulated by the snow and by this thick sheet of ice we've all been enjoying. It can be -25C air temp but it'll be less cold below. (Not sure about heat loss through ice though, I must admit I'm skating on thin ice here myself.)
So what about the noise? Because we have large areas of dense hard ice sheet, it acts like a giant sounding board amplifying any vibration. You can hear the hollow sound when you walk on top of it. The source of the vibration would come from the ice sheet not the ground. The above ground ice would expand as it froze further (perhaps the atmospheric humidity it absorbed throughout the day or the minute amounts of melt water from any solar heating). This freezing and consequent expansion would create internal pressure within the icesheet which would be relieved by cracking - like a pond does or the sea. On a large scale this would manifest in heaving fault lines or zastrugi.
My 2 centigrades worth. Thanks for your time.