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.

V_p (km/s)

Required number in km/s. P-wave velocity.

V_s (km/s)

Required number in km/s. S-wave velocity.

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

Compute Vp/Vs and the implied Poisson ratio, flagging unphysical values. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Vp/Vs

Returned number. Velocity ratio.

ν

Returned number. Implied Poisson ratio.

Valid

Returned boolean. Whether ν is physical (0 ≤ ν < 0.5).

• 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.
• V_p must be at least 0.
• V_s 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.

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