Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

Mean magnitude

Mean magnitude of the catalog above completeness.

Completeness

Completeness (minimum) magnitude of the catalog.

Aki (1965) maximum-likelihood b value of the Gutenberg-Richter law log10 N = a - bM: b = log10(e) / (mean magnitude - completeness magnitude). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

b value

Gutenberg-Richter b value (dimensionless).

• Seismic magnitudes, moments, travel times, velocities, resolution, and energy depend on instrument correction, Earth model, phase picking, geometry, attenuation, radiation pattern, bandwidth, and calibration range. Magnitude scales are not universally interchangeable.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• Richter Magnitude From Amplitude Calculator

  Original Richter (1935) local magnitude ML = log10(A / A0), comparing maximum Wood-Anderson trace amplitude in millimeters with the zero-magnitude reference amplitude at the same epicentral distance (0.001 mm at 100 km by definition).

• Seismic Energy Calculator

  Gutenberg-Richter energy relation log10 E = 1.5 M + 4.8 with E in joules, also expressed in tons of TNT (4.184e9 joules per ton).

• Moment Magnitude Calculator

  Hanks-Kanamori moment magnitude Mw = (2/3)(log10 M0 - 9.1) with seismic moment M0 in newton meters.