worm grunting n.— «Earthworms are sensitive to low-frequency vibrations. These drive some types of earthworms to the surface, and in the southeastern US is used in a practice known as “worm grunting,” by scraping a piece of metal on...
thumper truck n.— «Dawson has deployed three trucks to test 30-square miles that cover neighborhoods and non-residential areas in and around Fort Worth. The trucks emit a vibration into the ground ranging from 10-120 hertz. Small white...