On Monday, the Geological Survey of Denmark and Greenland...said the tremors were "not caused by earthquakes, but by pressure waves from an event in the atmosphere." However, they came from "an unknown source." On Saturday, GEUS said it had received "more than 60" tips from people on Bornholm that "earthquake-like tremors"—described as a deep rumbling, shaking and rattling, changing pressure in the ear—had been reported in the afternoon on Bornholm. No one was hurt. Police said they too were contacted by members of the public about the tremor on the eastern part of the island. Danish media reported that the...