Micro-Fracture Accompanied with Aftershocks

Aftershocks driven by afterslip and fluid pressure sweeping through a fault-fracture mesh

Renormalization of earthquake aftershocks

Assume that each earthquake can produce a series of aftershock independently of its size according to its “local” Omori’s law with exponent 1+θ. Each aftershock can itself trigger other aftershocks and so on. The global observable Omori’s law is found to have two distinct power law regimes, the first one with exponent p− = 1− θ for time t < t ∗ ∼ κ−1/θ, where 0 < 1−κ < 1 measures the fraction o...

Mechanical origin of aftershocks

Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that posi...

Moment Released by Aftershocks

In constructing moment-balanced fault rupture models for the SF Bay region, WG99 needed to account for all the moment released by earthquakes in the region. These include earthquakes on characterized rupture sources, earthquakes on other rupture sources (background), and their aftershocks. Some of the aftershocks will be large, with magnitudes sometimes exceeding 6.7. WG99 assumed that an after...

Postseismic response of repeating aftershocks

The recurrence intervals of repeating earthquakes on the San Andreas Fault in the Loma Prieta aftershock zone follow the characteristic 1/t decay of Omori’s law. A model in which these earthquakes occur on isolated patches of the fault that fail in stick-slip with creep around them can explain this observation. In this model the recurrence interval is inversely proportional to the loading rate ...