A Earthquake Energy computes earthquake energy from the inputs you provide. It applies the standard formula to the values you enter and returns the result instantly, without sending any data to a server. Free Earthquake Energy. The tool runs entirely.
Each magnitude = 32× more energy. M7 = 1000× M5.
Energy Released
Richter and moment magnitude scales are logarithmic. Each whole number = 32× energy. M7 = 1000× M5. M9 (Japan 2011) released ~25M Hiroshima bombs of energy. Surface effects also depend on depth, soil, distance.
This calculator converts an earthquake's magnitude into the seismic energy it radiates, the energy carried away as ground-shaking waves. Magnitude scales such as Richter and moment magnitude (Mw) are logarithmic, so the friendly one-digit numbers in news reports hide an explosive growth in actual energy: each step up the scale represents roughly 32 times more released energy.
The conversion uses the Gutenberg-Richter energy-magnitude relation, developed by Beno Gutenberg and Charles Richter in the 1950s and still the standard empirical link between magnitude and energy. Understanding it explains why a magnitude 8 is not merely a third worse than a magnitude 6 but about a thousand times more energetic, and why the largest recorded quakes dwarf the entire planet's nuclear arsenal in raw energy terms.
The Gutenberg-Richter relation gives radiated seismic energy as a logarithmic function of magnitude. In joules the standard form is below; in the older erg unit the constant is 11.8 instead of 4.8.
log10(E) = 1.5 M + 4.8 (E in joules)
E = 10^(1.5 M + 4.8)
Energy ratio between magnitudes M2 and M1:
E2 / E1 = 10^(1.5 (M2 - M1))
= 31.6 per unit of magnitude
How much seismic energy does a magnitude 6.0 earthquake radiate, and how does it compare to a magnitude 7.0?
Approximate radiated seismic energy and a familiar comparison for each magnitude, using log E = 1.5M + 4.8.
| Magnitude | Seismic energy (J) | Rough equivalent |
|---|---|---|
| 4.0 | 6.3 x 10^10 | Small quarry blast |
| 5.0 | 2.0 x 10^12 | Moderate, felt widely |
| 6.0 | 6.3 x 10^13 | ~15 kilotons of TNT |
| 7.0 | 2.0 x 10^15 | Major, regional damage |
| 8.0 | 6.3 x 10^16 | Great, ~1,000x a magnitude 6 |
| 9.0 | 2.0 x 10^18 | 2011 Japan, 2004 Sumatra class |
About 32 times more. The Gutenberg-Richter energy relation log E = 1.5M + 4.8 means each full unit of magnitude multiplies radiated energy by 10 to the power 1.5, which is about 31.6. So a magnitude 7 releases roughly 32 times the seismic energy of a magnitude 6, and a magnitude 8 releases about 1,000 times the energy of a magnitude 6.
Earthquakes span an enormous range of size, from imperceptible tremors to events that release more energy than thousands of nuclear weapons. A logarithmic scale compresses that range into manageable numbers: each one-point rise in magnitude is a tenfold increase in ground-motion amplitude and about a 32-fold increase in energy. Without it, magnitudes would need to span many orders of magnitude in raw units.
The original Richter scale (local magnitude) was calibrated for moderate Southern California quakes recorded on a specific instrument and saturates for large events above about magnitude 7. Moment magnitude (Mw), used by seismologists today, is based on the seismic moment, the actual physical work done by the fault rupture, and does not saturate, so it accurately measures the largest earthquakes.
The 2011 Tohoku earthquake registered moment magnitude 9.0 to 9.1. Using log E = 1.5M + 4.8, a magnitude 9.0 radiates about 2 times 10 to the 18 joules of seismic energy, equivalent to roughly tens of millions of tons of TNT. The total energy released, including heat and rupture work, was far larger than the seismic energy radiated as waves.
No. It gives the total seismic energy radiated by the rupture from its magnitude. What you actually feel at a given location depends on the earthquake's depth, distance, and the local soil and rock, which can amplify or dampen shaking. A deep magnitude 6 can feel milder at the surface than a shallow magnitude 5 directly beneath you.