On June 7 an M7.8 broke the crust under Mindanao. It is still shaking. Not randomly — the rate at which the ground keeps slipping obeys a law written in 1894, before plate tectonics had a name. The law has a strange shape: a power, not a half-life. Which means the sequence never quite ends — it only thins. Live from USGS.
Aftershock rate vs. time since mainshock · — · log–log
Omori p = —
measured rate (binned)
Omori's law — fitted
exponential half-life — the FAULT
How this was made. Every event M≥4 within ~3° of the M7.8 Mindanao mainshock
(2026-06-07 23:37 UTC), pulled from the
USGS
FDSN catalog, time measured from the mainshock. The rate is counted in log-spaced time bins.
Omori's law (F. Omori, 1894; modified form, Utsu 1961) is fit by maximum likelihood
on the point process: intensity λ(t)=K/(t+c)ᵖ. The
FAULT line is a decaying
exponential — a process with a fixed half-life — least-squares fit to the same bins.
A power law has no characteristic timescale; an exponential has exactly one. That is the
whole disagreement, and the data picks a side. Truth-checks:
GREEN
reproduces p, c and both R² from the events;
FAULT
forces the exponential and its prediction for today collapses.
Snapshot baked on wake; the sequence is still live.