Site Class NEHRP From VS30 Lookup
NEHRP site class (A–E) from time-averaged shear velocity.
Description
NEHRP site class (A–E) from time-averaged shear velocity.
Site Class NEHRP From VS30 Lookup is a focused tool for the following task. NEHRP site class (A–E) from time-averaged shear velocity. It reports Class, Description from the values you provide rather than inventing measurements, coefficients, or professional judgment that are not part of the input.
When to use Site Class NEHRP From VS30 Lookup
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.
- VS30 (m/s)
- Required number in m/s. Time-averaged shear velocity in the top 30 m.
The cited overview of Seismic site effects supplies background for the terminology and domain context used by this tool.1
How Site Class NEHRP From VS30 Lookup works
NEHRP site class (A–E) from time-averaged shear velocity. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.
- Class
- Returned string. NEHRP site class letter.
- Description
- Returned string. Soil/rock description for the class.
Limitations and assumptions
- 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.
- VS30 must be at least 0.
- Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.
Alternative or Complementary approaches
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.
References
-
Seismic site effects — Wikipedia contributors
Similar or alternative tools
- VS30 Time Averaged Shear Velocity Calculator
Time-averaged shear velocity over the top 30 m: VS30 = 30 / Σ(dᵢ/Vsᵢ).
- NEHRP Fundamental Period Site Lookup
Site fundamental period Ts = 4H/Vs from a NEHRP class-typical profile depth and velocity.
- Site Kappa Zero By NEHRP Class Lookup
Typical near-surface kappa ranges by NEHRP site class.