Use this seismology calculation to reproduce a stated convention, screen observations, or compare scenarios whose units, coordinate conventions, catalog selection, and model assumptions are known.

M₀ (N·m)

Required number in N·m. Seismic moment.

γ

Optional number. Scaling exponent.

The cited overview of Fault (geology) supplies background for the terminology and domain context used by this tool.^[1]

Asperity area fraction A_a/A₀ as a power-law function of seismic moment, capped at the physical upper bound of one. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

A_a/A₀

Returned number. Asperity area fraction.

• Earth structure, source geometry, path effects, site response, instrument response, catalog completeness, uncertainty, and the fitted range can dominate the accuracy of simplified seismic calculations.
• M₀ must be at least 0.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

For analysis or hazard decisions, retain uncertainty and provenance and compare the result with waveform processing, calibrated regional models, and guidance from qualified seismologists or the responsible agency.

• Seismic Landslide Area Volume Scaling Calculator

  Empirical area-volume scaling for seismically triggered landslides: V = α·A^γ (Guzzetti-like).

• Seismic Moment To Slip Displacement Back Calc

  Average slip from moment and area: D = M₀/(μ·A).

• Aftershock Zone Length Utsu Scaling Calculator

  Utsu aftershock-zone scaling: log₁₀L(km) = 0.5·M − 1.8, with equivalent area.