How earthquake magnitude relates to energy
Earthquake magnitude scales (like the moment magnitude scale, Mw, used for most modern reporting) are logarithmic. Each whole-number increase in magnitude represents about 10 times more ground motion amplitude, but roughly 31.6 times more energy released, because energy grows with the 1.5 power of amplitude.
How this calculator works
Enter a magnitude, and the calculator applies the standard Gutenberg-Richter energy-magnitude relation: log₁₀(E) = 1.5M + 4.8, where E is energy in joules. It converts that energy into an approximate TNT equivalent (dividing by 4.184 × 10⁹ joules per ton of TNT) for an intuitive sense of scale, and compares the earthquake to a second magnitude you enter — showing how many times more energy it released and how many times larger the ground-shaking amplitude was.
- A magnitude 7.5 earthquake releases roughly 31.6 times more energy than a magnitude 6.5 earthquake, and about 1,000 times more than a magnitude 5.5 earthquake.
- Real-world damage also depends heavily on depth, distance, local geology, and building design, not energy alone.
This tool is for general educational purposes and uses a standard published approximation; it is not a substitute for official seismological data from agencies like the USGS.