Shear Wave Velocity Calculator

Shear wave velocity, commonly written as Vs, is the speed at which a transverse elastic disturbance travels through a solid material. In a shear wave, particles move perpendicular to the direction in which the wave propagates. Fluids cannot sustain static shear stress, so this relationship is mainly useful for solids, soils, and rock. Vs is a fundamental property in seismology, geotechnical engineering, nondestructive testing, and materials science because it links measurable wave behavior to mechanical stiffness. This calculator uses the elastic relationship Vs = square root of (G divided by density). G is the shear modulus, which measures resistance to shear deformation, and density is mass per unit volume. The interface accepts G in gigapascals and converts it to pascals before applying the equation. Density is entered in kilograms per cubic meter, producing velocity in meters per second. Both values must be positive. A stiffer material raises wave speed, while a denser material lowers speed when stiffness remains unchanged. Reliable input data matters. Shear modulus can vary with temperature, pressure, porosity, moisture, strain level, and material orientation. Soil values measured at very small strain may differ substantially from values under working loads. Likewise, bulk density should represent the same specimen and condition as the modulus. If a source provides unit weight rather than density, convert it before calculating. For anisotropic composites or fractured rock, one scalar modulus may not capture direction-dependent behavior. Engineers use Vs to classify sites, estimate dynamic soil response, interpret seismic surveys, and infer elastic properties. Geophysicists compare velocity layers to identify subsurface boundaries. Materials laboratories use ultrasonic measurements in the reverse direction to estimate modulus when density is known. This calculator provides a transparent first calculation for those tasks, but it does not replace a full site investigation, dispersion analysis, or constitutive model. Keep enough significant figures for intermediate work, then round the final speed to match the precision of the measured inputs.