- a relatively small earthquake that precedes a greater one by a few days or weeks and originates at or near the focus of the larger earthquake.
Origin of foreshock
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- a relatively small earthquake heralding the arrival of a much larger one. Some large earthquakes are preceded by a series of foreshocksCompare aftershock
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012