Foreshock 5 : Natural Disaster. An earthquake that precedes the largest quake ("mainshock") of an earthquake sequence. Foreshocks may occur seconds to weeks before the mainshock
U.S. Department of the Interior,U.S. Geological Survey, Putting Down Roots in Earthquake Country (Your Handbook for the San Francisco Bay Region), Glossary, Denver, CO, USA 2006. http://pubs.usgs.gov/gip/2005/15/#glossary, http://bhs.idaho.gov/pages/Preparedness/Hazards/PD F/Putting%20Down%20Roots%20in%20EQ%20Country.pdf, (ND/ Erthq - Brit) {897}