And they found the wetter location was alive with seismic activity at night.
“In these ponds, there’s often a layer of ice on top of melted water below, like you see with a lake that’s only frozen on top,” Professor MacAyeal explained.
“As the temperature cools at night, the ice on the top contracts, and the water below expands as it undergoes freezing.
“This warps the top lid, until it finally breaks with a snap.”
The energy vibrates out into the surroundings, where it is recorded by seismometers.
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