Triggered seismicity

Triggered seismicity refers to earthquakes that are initiated by external perturbations — such as the stress changes produced by nearby fault ruptures, fluid injection, reservoir impoundment, or volcanic activity — rather than by the gradual accumulation of \'\'\'tectonic loading\'\'\' alone. The concept challenges the traditional view of earthquakes as independent random events, revealing instead a coupled network in which the occurrence of one rupture changes the probability of others. After a large earthquake, the surrounding crust experiences \'\'\'Coulomb stress changes\'\'\' that can either advance or delay failure on neighboring faults. This stress transfer mechanism is the physical basis for \'\'\'aftershock sequences\'\'\' and for the observation that major earthquakes sometimes cluster in space and time. Triggered seismicity demonstrates that the earthquake system has \'\'\'memory\'\'\': the probability of future events depends on the history of past events, not merely on the current state of stress.