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.

f₀ (Hz)

Required number in Hz. Geophone natural frequency.

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

Response corner and usable band for common geophone classes by natural frequency. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

f_low (Hz)

Returned number in Hz. Lower edge of the usable flat band (~1.2·f₀).

T₀ (s)

Returned number in s. Corner period.

Class

Returned string. Typical deployment class.

• 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.
• f₀ 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.

• Response Spectrum Corner Period Band Lookup

  Acceleration- and velocity-controlled period bands scaled by magnitude class.

• Brune Displacement Spectrum Peak Frequency Note

  For the Brune model, displacement amplitude peaks exactly at the corner frequency.

• Corner Frequency Stress Drop Consistency Checker

  Invert the Brune relation fc = 0.49·β·(Δσ/M₀)^(1/3) for stress drop Δσ = M₀·(fc/(0.49·β))³ given the moment and compare with a claimed Δσ; no rigidity term is needed because Δσ/M₀ replaces it.