What is a foreschock?

Answer 1

A foreshock is a smaller seismic event that occurs before a larger earthquake, known as the mainshock. Foreshocks can happen minutes, days, or even weeks prior to the main event and are often located in the same area. While they can signal an impending larger quake, not all earthquakes have foreshocks, and not all foreshocks are followed by significant mainshocks. Understanding foreshocks can help seismologists assess earthquake risk, but predicting specific events remains challenging.