Live global aftershock tracker providing real-time algorithmic detection of post-seismic sequences following Omori's Law and fault rupture dynamics across active plate boundaries.
Real-time USGS seismic table displaying the 10 most recent earthquakes and latest earthquakes recorded today with verified moment magnitude (Mw), epicenter location, and focal depth.
When a major earthquake ruptures a fault line, the tectonic stress across adjacent crustal rocks is not instantly equalized. The surrounding earth undergoes post-seismic readjustment through secondary fractures known as aftershocks, which gradually restore mechanical equilibrium along the fault plane.
Yes, though it occurs in less than 5% to 10% of seismic sequences. If a subsequent tremor exceeds the magnitude of the initial earthquake, seismologists reclassify the initial shock as a "foreshock", and the new, larger tremor becomes the new "mainshock".
Aftershocks follow Omori's Law of temporal decay, meaning tremor frequency drops hyperbolically over time. For moderate events (M5.0 to M6.0), aftershocks typically diminish within days to weeks. For severe subduction megathrust earthquakes (M7.0 to M9.0), secondary tremors can reverberate for months or even years.
Båth's Law is an empirical seismological principle stating that the difference in magnitude between a mainshock and its largest aftershock averages approximately 1.2 magnitude units, irrespective of the absolute size of the initial earthquake.