Following a major earthquake, can more large earthquakes be expected?
Yes, following a major earthquake the region can expect to experience many large aftershocks . These aftershocks usually occur geographically near the main earthquake. The stress on the main shock's fault changes drastically during the earthquake and that fault produces most of the aftershocks. Sometimes the change in stress caused by the main shock is great enough to trigger aftershocks on other, nearby faults. As shown below, aftershock sequences follow predictable patterns as a group, although the individual earthquakes are themselves not predictable. The number of aftershocks and the magnitude of aftershocks decay with increasing time, though they can occur months or even years after the main shock.