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.

fs (Hz)

Required number in Hz. Sampling rate.

f_c (Hz)

Required number in Hz. Low-pass corner.

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

Check that a low-pass corner sits safely below the Nyquist frequency of the sample rate. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

f_N (Hz)

Returned number in Hz. Nyquist frequency.

f_c/f_N

Returned number. Corner as fraction of Nyquist.

OK?

Returned boolean. Whether the corner is at or below 80 percent of Nyquist.

• 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.
• fs must be at least 0.
• f_c 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.

• Microtremor Array Resolution Frequency Band Checker

  Check that array aperture brackets the wavenumbers of the target frequency band for SPAC/f-k dispersion work.

• Bath Law Largest Aftershock Gap Note Lookup

  Båth's law: the largest aftershock sits about 1.2 magnitude units below its mainshock.

• Brune Corner Frequency Source Model Calculator

  Compute the Brune (1970) circular-crack corner frequency fc = 4.9e6·β·(Δσ/M₀)^(1/3) with β in km/s, Δσ in bar, and M₀ in dyn·cm.