From AMS Glossary
Revision as of 19:35, 26 January 2012 by Perlwikibot
Low, rumbling thunderlike sounds of short duration not originating from thunderstorms and believed to be of seismic origin.
Different local names are used for this phenomenon in different parts of the world.
Gold, T., and S. Soter 1979. Science. 204. 371–375.