earthquake lights
n.pl.— «Piccardi explained that frictional heating, electron emissions, luminescence resulting from sound, and electrical charge changes that momentarily turn rocks into semiconductors all can result in what he and the U.S. Geological Survey refer to as “earthquake lights.”» —“St. Michael’s Apparition, Earthquake Linked” by Jennifer Viegas Discovery Channel Jan. 9, 2006. (source: Double-Tongued Dictionary)