Does this predict the next aftershock?

No. It shows expected rates and frequency distributions from simple empirical laws. Individual aftershocks are stochastic and operational models require uncertainty and spatial information.

What does a larger b-value mean?

A larger b-value steepens the magnitude-frequency curve, meaning relatively more small events and fewer large events above the completeness magnitude.

Earthquake Aftershocks: Omori + Gutenberg-Richter

Modified Omori aftershock decay n(t)=K/(t+c)^p combined with Gutenberg-Richter magnitude-frequency curves, b-value, and a synthetic catalog.

Real operational aftershock forecasts include spatial kernels, mainshock magnitude scaling, catalog incompleteness, and uncertainty. This page isolates the two classic empirical laws so their slopes and time scales are easy to read.

Live graphs

About this model

Aftershock sequences are often summarized by two empirical laws. The modified Omori law n(t)=K/(t+c)^p describes how the event rate decays after the mainshock; integrating it gives the expected cumulative number N(t). The Gutenberg-Richter relation log10 N(M>=m)=a-bm describes how magnitudes are distributed, with b-value controlling the relative abundance of small and large events. This simulator plots rate and cumulative curves, a deterministic synthetic catalog, and the magnitude-frequency line. It is a teaching diagnostic rather than an operational forecast: no spatial kernels, mainshock scaling, catalog incompleteness correction, branching ETAS triggering, or uncertainty bands are included.

Who it's for: Seismology, natural hazards, statistics, or introductory geophysics modules.

Key terms

Omori law
Gutenberg-Richter law
b-value
Aftershock rate
Magnitude-frequency distribution

How it works

Aftershock sequence sketch combining modified Omori decay n(t)=K/(t+c)^p with the Gutenberg-Richter magnitude-frequency relation log10 N=a-bM.

Key equations

n(t) = K / (t + c)^p; N(t) = integral n(t) dt

log10 N(M >= m) = a - b m; larger b means relatively more small events

Frequently asked questions

Does this predict the next aftershock?: No. It shows expected rates and frequency distributions from simple empirical laws. Individual aftershocks are stochastic and operational models require uncertainty and spatial information.
What does a larger b-value mean?: A larger b-value steepens the magnitude-frequency curve, meaning relatively more small events and fewer large events above the completeness magnitude.

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About this model

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Frequently asked questions

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Live graphs

About this model

How it works

Key equations

Frequently asked questions