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Compare Two Magnitudes.

A jump of one on the Richter scale is 10× the ground-motion amplitude and about 32× the radiated energy. This calculator helps visualize the big difference between two magnitudes.

Magnitude Comparison

Richter-style amplitude is 10× per unit. Radiated energy is ~32× per unit. Those are different logarithms.

How much bigger is B than A?

Amplitude B/A

100×

10^ΔM · wiggle height

Energy B/A

1,000×

10^(1.5 ΔM) · radiated Es

ΔM (B − A)·+2.0

Shared log scale — 1× at center; energy outruns amplitude

Amplitude 10^ΔM100× B/A
Energy 10^(1.5 ΔM)1,000× B/A
10⁻⁶×10⁻³×10³×10⁶×

How many A quakes match one B in energy

1,000× (tiles capped at 64)

Quake B alone (not a ratio)

Radiated energy Es

7.94×10¹⁴ J

TNT equivalent (order of magnitude)

189.85 kt TNT

Seismic moment M₀

4.03×10¹⁹ N·m

Same station, amplitude ∝ 10^M

Relative amplitude+10-1+10-1CH-A M5.0CH-B M7.0

This plot shows amplitude — how tall the wiggle is. The larger quake fills the frame; the smaller is drawn 0.01× as tall. Height scales by 10× per magnitude unit. Energy is steeper: about 32× more radiated energy for each +1 magnitude, so a modest height gap can hide a much larger energy jump.

Two slopes vs ΔM

-2-10+1+210⁻⁴×10⁻³×10⁻²×10⁻¹×10¹×10²×10³×10⁴×ΔM (B − A)B/A (log)Amplitude 10^ΔMEnergy 10^(1.5 ΔM)

Both curves start at 1× when ΔM = 0. Amplitude rises as 10^ΔM (slope 1 on this log plot). Energy rises as 10^(1.5 ΔM) (slope 1.5) — steeper, so it peels away. Your pair sits at ΔM = +2.0.

Limitations

  • Original Richter magnitude (ML) is a local Wood-Anderson amplitude. It saturates above ~M 6.5. Energy and moment here treat the number as moment magnitude Mw.
  • Amplitude ratio assumes the same distance and instrument. Felt intensity (MMI) is not magnitude.
  • Es = 10^(1.5M + 4.4) J is Kanamori’s radiated-energy estimate, not total strain energy on the fault. TNT is an order-of-magnitude metaphor only.

The Math

Magnitude is a logarithm of size. Amplitude and energy use different slopes on that log, which is why +1 looks modest on a seismogram and enormous in joules.

Amplitude

A ∝ 10^M

Richter local magnitude ML, same station and instrument. Ratio B/A = 10^(ΔM). Each +1 is 10×.

Radiated energy

log₁₀(Es) = 1.5M + 4.4

Kanamori (1977), Es in joules. Ratio B/A = 10^(1.5 ΔM) ≈ 31.6× per unit.

Seismic moment

M₀ = 10^(1.5(Mw + 6.07))

Hanks & Kanamori, M₀ in N·m. Energy and moment treat the input as Mw.

TNT equivalent

1 t TNT = 4.184×10⁹ J

Order-of-magnitude metaphor only. Es is radiated seismic energy, not a blast yield.

ML saturates above ~M 6.5. Amplitude ratios assume the same distance. Felt intensity (MMI) is not magnitude.