Earthquake Energy Calculator

How to Use This Calculator

1. Enter the earthquake magnitude (moment magnitude Mw).
2. See energy in joules, TNT equivalent, and a nuclear comparison.
3. Use Compare Two Earthquakes tab to see the energy ratio between any two events.
4. Use Equivalent Comparisons tab for Hiroshima bomb and Tsar Bomba equivalents.
5. Professional mode adds megatons and a reference-magnitude ratio.

Formula

Example

Frequently Asked Questions

• How much energy does an earthquake release? ▼
  The energy released by an earthquake spans an extraordinary range — from tiny micro-earthquakes releasing less than a thousand joules (comparable to a light bulb burning for a few seconds) to the most powerful events releasing over 10²⁰ joules. The relationship between moment magnitude Mw and energy E is: E = 10^(1.5·Mw + 4.8) joules. A magnitude 5.0 releases about 2×10¹² J — roughly equivalent to a small nuclear warhead. A magnitude 6.0 releases ~6×10¹³ J, comparable to the Hiroshima atomic bomb. A magnitude 8.0 releases ~6×10¹⁶ J, and the 1960 Chile Mw 9.5 earthquake released approximately 10²⁰ J — more energy than all other 20th-century earthquakes combined. Not all of this energy reaches the surface as shaking; roughly 95% is dissipated as heat along the fault, with only a few percent radiated as seismic waves.
• Why does each magnitude unit represent 32× more energy? ▼
  The energy-magnitude relationship uses an exponent of 1.5: E = 10^(1.5·M + constant). When magnitude increases by 1, the energy multiplier is 10^1.5 = 31.62, commonly rounded to 32. This factor of 1.5 in the exponent was established empirically by Beno Gutenberg and Charles Richter in the 1950s and later confirmed through physical reasoning by Kanamori and others. The ground motion amplitude (how hard the ground actually shakes) scales by a factor of 10 per magnitude unit, while energy scales as amplitude squared times velocity — introducing the extra factor of √10 ≈ 3.16, giving 10 × 3.16 ≈ 31.6× total. A practical consequence: two magnitude units equals 1,000× more energy (31.6²), and three magnitude units equals about 31,600× more energy. This is why the difference between a M8 and a M6 event is not "twice as bad" but roughly a thousand times more energetic.
• How does an earthquake compare to nuclear bombs? ▼
  The comparison is striking and widely cited. The Hiroshima atomic bomb released approximately 6×10¹³ J (roughly 15 kilotons of TNT), equivalent to about a magnitude 6.0 earthquake in energy. The Tsar Bomba — the largest nuclear device ever detonated, by the Soviet Union in 1961 — released about 2.1×10¹⁷ J (50 megatons TNT), equivalent to roughly a magnitude 8.4 earthquake. The 1960 Chile earthquake (Mw 9.5) released approximately 10²⁰ J — equivalent to about 1,700 Tsar Bombas or nearly 2 million Hiroshima bombs. However, the comparison has limits: nuclear explosions are surface or near-surface events that release energy in milliseconds, while earthquakes release energy over seconds to minutes across hundreds of kilometers of fault. The spatial distribution of energy matters enormously for shaking and damage patterns.
• What is the energy of the largest recorded earthquake? ▼
  The 1960 Valdivia earthquake in Chile (Mw 9.5) is the largest instrumentally recorded earthquake in history. It released approximately 1.1×10²⁰ joules of seismic energy, equivalent to about 26 billion tons of TNT or roughly 1,700 Tsar Bombas. The rupture extended along roughly 1,000 km of the Nazca-South American plate boundary, with average fault slip of around 15–20 meters. The earthquake generated a destructive trans-Pacific tsunami that caused casualties in Hawaii, Japan, and the Philippines. Other great earthquakes — 1964 Alaska Mw 9.2, 2004 Indian Ocean Mw 9.1, 2011 Tōhoku Mw 9.0 — each released between 10^18.5 and 10^19.7 joules, one to two orders of magnitude less than the 1960 Chile event, illustrating again the enormous energy differences compressed into small magnitude differences.
• How is earthquake energy converted to surface shaking? ▼
  Only a small fraction of total earthquake energy — typically 1–10% — is radiated as seismic waves that cause surface shaking; the remainder is dissipated as heat, sound, and fracturing rock along the fault. The seismic waves that reach the surface are classified into body waves (P-waves and S-waves) and surface waves (Love and Rayleigh waves). S-waves and surface waves carry most of the destructive shaking energy experienced at the ground surface. The intensity of shaking at any given location depends on source energy, distance, focal depth, wave path attenuation, and critically, local site conditions. Soft sedimentary basins can amplify shaking by factors of 5–10 compared to bedrock — a phenomenon that caused catastrophic damage in Mexico City during the 1985 earthquake despite the epicenter being 350 km away. Engineers use these relationships in building codes via ground motion prediction equations (GMPEs).

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