PSHA Tool
Probabilistic Seismic Hazard Analysis | by Albert Pamonag
psha.apeconsultancy.net
Modules
| Module | Description |
|---|---|
| Declustering | Remove aftershocks using Gardner-Knopoff windows |
| Completeness Analysis | Magnitude-time density with completeness thresholds |
| Gutenberg-Richter | Recurrence parameter estimation (a, b-value) via MLE |
| UHS Generator | Interpolate Sa from OpenQuake hazard curves |
| DSHA | Deterministic Seismic Hazard Analysis |
| Deaggregation | 3D magnitude-distance-epsilon contribution |
| Response Spectrum | Smoothed design spectrum + BSDS Level I |
| Return Period | POE / lambda / MRP conversions |
| Spectra Plotter | Overlay and envelope multiple spectra |
Quick Start
- Upload earthquake catalog in Declustering
- Run Completeness and Gutenberg-Richter
- Upload OpenQuake outputs in UHS Generator and Deaggregation
- Generate design spectra in Response Spectrum
- Check the QAQC Log for audit trail
Declustering - Gardner-Knopoff Method
Remove aftershocks from earthquake catalog. Compare original vs declustered side-by-side.
Upload earthquake catalog CSV (time, latitude, longitude, depth, mag)
Completeness Analysis
Magnitude-time density analysis by depth class with completeness step curves.
Upload declustered catalog CSV (time, mag, depth)
Gutenberg-Richter Recurrence
Estimate a-value and b-value using Maximum Likelihood Estimation.
Upload declustered catalog CSV
Uniform Hazard Spectrum (UHS) Generator
Interpolate spectral accelerations from OpenQuake hazard curve CSVs.
Upload hazard curve CSVs (multiple files)
Deterministic Seismic Hazard Analysis (DSHA)
Calculate ground motion for maximum magnitude from fault sources.
Upload fault source CSV (fault_name, max_magnitude, distance_km)
Deaggregation Explorer
3D magnitude-distance-epsilon contribution from OpenQuake output.
Upload OpenQuake deaggregation CSV
Response Spectrum - Smoothed Design
Generate smoothed spectrum and compare with BSDS Level I.
Return Period Calculator
Convert between POE, Annual Exceedance Rate, and Mean Return Period.
Common Return Periods
| Scenario | Lambda | MRP (yr) |
|---|---|---|
| 10% in 50 yr | 0.002107 | 475 |
| 2% in 50 yr | 0.000404 | 2475 |
| 5% in 50 yr | 0.001026 | 975 |
| 10% in 75 yr | 0.001405 | 712 |
| 2% in 75 yr | 0.000270 | 3712 |
| 50% in 30 yr | 0.023105 | 43 |
Spectra Plotter - Overlay / Envelope
Upload spectra CSV files (multiple)
Change Log
PSHA Tool by Albert Pamonag
v1.1.0 (2026-03-29)
- Separated HTML/CSS/JS for easy manual editing
- Declustering: side-by-side original vs declustered comparison
- Mapbox GL interactive maps (if token provided)
- Modular page templates (templates/pages/*.html)
v1.0.0 (2026-03-29) - Initial Release
- Declustering module (Gardner-Knopoff method)
- Completeness analysis with magnitude-time density plots
- Gutenberg-Richter recurrence (MLE b-value estimation)
- UHS Generator from OpenQuake hazard curves
- DSHA module with configurable GMPE coefficients
- Deaggregation 3D explorer (magnitude-distance-epsilon)
- Response Spectrum with smoothed design + BSDS Level I
- Return Period Calculator (POE / lambda / MRP)
- Spectra Plotter with overlay and envelope
- Save / Load session (JSON export/import)
- QAQC audit log with checklist
- Flask + vanilla JS frontend (lightweight)
- Deployed on Railway at psha.apeconsultancy.net
Planned
- BSDS Level II with site factor interpolation
- OpenQuake direct integration
- PDF report generation
- Multi-site batch analysis
- User authentication