New one for me, never heard of this before.

Researchers solve seismic mystery that shook central Alberta communities
December 14, 2018 by Andrew Lyle, University of Alberta

Icequakes created by a unique combination of weather and buckling lake ice—not earthquakes—caused the tremors that damaged homes and properties in several central Alberta communities last New Year's Day, according to new research. "Central Alberta is a pretty seismically quiet place, so the fact that these tremors were felt in several communities across the region—and with this much power—is quite noteworthy," said University of Alberta geoscientist Jeffrey Kavanaugh, who worked with seismologists Mirko van der Baan and Ryan Schultz, and other researchers to solve the mystery of what caused the tremors. "Unlike most seismic activity, which is caused by tectonic stresses, these were caused by thermal stresses related to Alberta's cold climate." The quakes occurred on Lac Ste. Anne, Pigeon Lake and Gull Lake, and had a magnitude of 2.0 on the Richter scale, recorded on the Albertan regional seismic network.