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RSL III — 1D Site Response Analysis

RSL III is the GeoStru web software for site response analysis (SRA) on 1D soil columns. Given the site stratigraphy (layer thickness, Vs, ρ, G/Gmax-γ and ξ-γ degradation curves) and a bedrock input accelerogram, it computes the propagation of S waves to the surface using the equivalent-linear scheme (iterative Idriss-Seed) and returns the response spectrum, γ_max / a_max profiles and the ICMS amplification factors for Level 3 seismic microzonation (ICMS 2008/2018).

Open RSL III 5-minute Quickstart

What it does, in short

  • Input: stratigraphy (thickness, Vs, ρ, dynamic curves), bedrock accelerogram (real or synthetic), analysis type
  • Calculation: equivalent-linear scheme with successive iterations, until convergence of γ_eff (effective strain = 65% of γ_max)
  • Output:
  • Surface response spectrum (PSA or SA)
  • Input/output Fourier spectrum
  • Profiles along the vertical: γ_max, a_max, σ_max
  • ICMS amplification factors: FA, FH, FT (for Level 3 seismic zonation)
  • Multi-site mode: compare different columns (with one or more accelerograms), mean spectrum + statistics

Who it's for

  • Geologists producing seismic microzonation studies (ICMS Level 2 or 3) for municipalities
  • Earthquake engineers designing buildings and structures with a site-specific accelerogram instead of the standard NTC spectrum
  • Consulting studios integrating SRA analysis into a geotechnical report for construction in seismic zones

How to get started

  1. Open nx.geostru.ai/rsl/
  2. Load a sample or define the stratigraphy
  3. Load an accelerogram (or use a sample one)
  4. Press Run calculation
  5. Inspect response spectrum + profiles + ICMS
  6. Export the Word report

See the complete workflow →

Manual chapters

Getting started

Input

  • Input data — stratigraphy, degradation curves, input accelerogram, iteration parameters

Calculation

Output

Reference

  • FAQ — frequently asked questions

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