About Quake Compare
A small calculator that shows why amplitude and radiated energy scale differently when magnitude goes up by one.
What this is
Quake Compare lets you pick two magnitudes and see the amplitude ratio (10^ΔM), the radiated-energy ratio (~32× per unit), synthetic traces at the same station, and order-of-magnitude energy and moment for the larger event.
It is an educational tool, not a seismic network product, and not a substitute for USGS or other official earthquake information.
Where the numbers come from
Amplitude ratios follow Richter local magnitude (ML) for the same station and instrument. Radiated energy Es uses Kanamori (1977): log₁₀(Es) = 1.5M + 4.4 (joules). Seismic moment uses Hanks & Kanamori, treating the input as moment magnitude Mw. TNT is only an order-of-magnitude metaphor.
Original ML saturates above roughly M 6.5. Felt intensity (MMI) is not magnitude. See the limitations on the homepage for the rest of the caveats.
How the site stays up
Once Google approves a publisher account, labeled display ads may appear on the calculator page. See Privacy for cookies and opt-outs.