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.

ρ (kg/m³)

Optional number in kg/m³. Density.

V_p (km/s)

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

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

Compute the P-wave modulus M = ρ·Vp². Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

M (GPa)

Returned number in GPa. Constrained modulus.

• 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.
• 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.

• Air Coupled Rayleigh Wave Speed Calculator

  Rayleigh wave speed from shear velocity (≈0.92·β for ν = 0.25) compared with the speed of sound in air.

• Basin Edge Surface Waves Checker

  Screen whether the bedrock-to-basin shear-wave velocity contrast reaches an illustrative 2:1 threshold associated with stronger basin-edge effects; geometry is not modeled.

• 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.