PSHA Tool

Probabilistic Seismic Hazard Analysis · APEC Team

An interactive workbench for the PSHA workflow — source modeling and GMPEs, hazard curves and uniform hazard spectra, ground-motion conversion, scaling and spectral matching, near-fault effects, orbit visualization, and site response.

developed by Albert Pamonag and Camille Pajarillaga · psha.apeconsultancy.net

modules UHS · GMPE · BSDS SRSS · GeoMean · RotD Site Response

Seismic Hazard

UHS Generator Interpolate a uniform hazard spectrum from OpenQuake exports at a target return period. Hazard Curves Interpolate a UHS from OpenQuake hazard-curve CSVs at a target return period. BSDS Curve Plot a BSDS design response spectrum and read off A_s, S_DS, S_D1, T_s, T₀. UHS vs BSDS Bedrock Overlay a uniform hazard spectrum on a BSDS bedrock design spectrum; export PNG and comparison CSV. Return Period Calculator Convert between probability of exceedance, annual rate λ, and mean return period.

Source Model

SSM Visualizer Browse seismic source model XML grouped by tectonic region. Focal Mechanisms Focal-mechanism / nodal-plane visualization for faults near a site. Depth & Nodal Hypocentral depth distribution, PMF table, and OpenQuake hypoDepthDist XML. GMPE Comparison Compare GMPE attenuation curves, weighted mean, hazard envelope, and spectrum.

Ground Motion Records & Conversion

SeismoMatch to PEER (.AT2) Convert SeismoMatch output into PEER .AT2 acceleration records. AT2 Converter Resample and convert PEER .AT2 acceleration records. Arias Intensity Trim Trim .AT2 records to their D_5–95 significant-duration window; batch, same format out. QuakeManager → RSseismic Convert QuakeManager .AT2 records into RSseismic text input (NPTS DT header + time/acc columns). SeismoMatch → RSseismic Convert SeismoMatch matched accelerograms directly into RSseismic text input — no intermediate .AT2 step. PEER to TXT Export PEER records to plain-text time-history files. PEER FORMAT Convert OpenQuake hazard-spectrum results (<poe>~PGA / SA(T)) into a PEER “User Defined Spectrum” T, Sa CSV. GM Classification Classify ground-motion records by their input format.

Ground Motion Spectra & Matching

Seed Motion Compute the response spectrum of a seed record with OpenSeesPy. SpecMatReport Response-spectrum overlay report computed with OpenSeesPy. Mean Spectra Mean response spectra across bedrock/surface with BSDS comparison. Smooth Spectra Compare Overlay smoothed bedrock, surface, and BSDS code spectra; surface/bedrock amplification and surface-vs-code ratios. ShaCodeOverlay Overlay DSHA, PSHA, and code design response spectra. SurCodeOverlay Overlay surface mean spectra (X/Y) vs BSDS; site-specific smoothing and ⅔-BSDS envelope, per direction. Surface X/Y Combine — GeoMean / SRSS Combine two DEEPSOIL surface mean spectra (X/Y) into one horizontal spectrum by geometric mean & SRSS; PGA / 0.2s / 1.0s table and optional BSDS overlay. SpecCombine — SRSS / GeoMean / RotD Combine two horizontal .AT2 components into SRSS, geometric-mean, RotD50, and RotD100 spectra (Boore 2010) — four plots + CSV.

Ground Motion Near-Fault & Baseline

Fling Figure Add a tectonic fling step to the fault-parallel component and compare records. Pulse / Non-Pulse Classification Detect pulse-like (forward-directivity) records via the Baker (2007) wavelet algorithm: Pulse Indicator, T_p, PGV. Corrected Ground Motion Baseline-correct acceleration records (HP 0.05 Hz) and export the corrected motions. Corrected GM — Disp Baseline (Test) Experimental displacement-domain (polynomial) baseline; exports .txt + .AT2.

Ground Motion Orbit & Polar

Polar Plot Polar plot of ground-motion components. Displacement Polar Particle-motion displacement orbit, double-integrated from acceleration. Displacement Orbit Compare Compare displacement orbits across SEED, Match, and Surface stages. Animated Orbit Plot Animate the displacement orbit of one X/Y pair — a moving particle with synced acceleration & displacement time histories.

Ground Motion Site Response

DEEPSOIL Results Visualize DEEPSOIL site-response output. DEEPSOIL to TXT Export DEEPSOIL results to plain-text time histories. DEEPSOIL Mean Spectra Mean response spectra from DEEPSOIL site-response outputs. GM Outcrop vs Surface Per-record PGA/PGV/PGD for bedrock outcrop vs site-response surface, auto-paired by station, with a median row.

Tip: use the search box to jump to a module, or open the Change Log for version history.

Uniform Hazard Spectrum (UHS)

Plot an OpenQuake UHS (hazard_uhs) export — columns are POE~IMT and the values are spectral accelerations. A single-POE file is plotted as-is at the return period that POE implies; a multi-POE file is interpolated to the target return period below. For raw hazard-curve CSVs, use the Hazard Curves page instead.

Upload an OpenQuake UHS CSV (hazard_uhs export)

Investigation time (yr)

Target return period (yr)

BSDS Curve Generator

Upload a BSDS design-spectrum data file — columns Period(s), Acceleration(g), and optionally 2/3 Acceleration(g) (tab, space, or comma separated; a header row is ignored) — to plot the design response spectrum and read off its key parameters.

Upload BSDS data file (.txt / .csv)

Axis scale

Show 2/3 curve

UHS vs BSDS Bedrock

Overlay a uniform hazard spectrum (UHS) on a BSDS bedrock design spectrum for a side-by-side comparison. Upload the UHS export (OpenQuake hazard_uhs CSV, or a simple period, Sa table) and the BSDS bedrock CSV (Period (s), Sa (g), 2/3 Sa (g)). The result is a log–log overlay (PNG) plus a comparison table (CSV) carrying the UHS/BSDS ratio over the overlapping period band.

Upload UHS CSV (OpenQuake hazard_uhs or period, Sa)

Upload BSDS bedrock CSV (Period, Sa, 2/3 Sa)

Hazard Curves → UHS

Interpolate spectral accelerations from OpenQuake hazard-curve CSVs (one IMT per file, poe-* columns) at a target return period, then assemble the Uniform Hazard Spectrum. Upload one curve per spectral period (PGA, SA(0.2), SA(1.0), …). For an already-computed UHS export, use the UHS Generator page instead.

Upload OpenQuake hazard-curve CSVs (one per IMT, multiple files)

Investigation time (yr)

Target return period (yr)

Return Period Calculator

Convert between POE, Annual Exceedance Rate, and Mean Return Period.

Mode

POE (%)

Time period (yr)

Lambda

Return Period (yr)

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

Depth Distribution & Nodal Planes

Hypocentral depth histogram and PMF table for OpenQuake source model input.

Upload earthquake catalog (.csv, .hmtk)

Focal Mechanisms & Nodal Planes

View fault parameters per SSM source within 300 km. Select a fault to see its geometry, MFD, and nodal plane parameters.

Select Fault Source (within 300 km)

SSM Source Model Visualizer

Visualize PHIVOLCS-GEM seismic source model: fault traces, area zones, and MFD parameters.

Crustal Sources

Subduction Interface

Subduction Slab

Show Interactive Mapbox Map

Or upload custom SSM XML files:

Upload SSM XML (.xml)

GMPE Comparison

Philippine GMPE reference (PHIVOLCS-GEM-Oct2020) with distance-attenuation comparison plots.

Tectonic Region

GMPEs

Parameters

Magnitude

Min Distance (km)

Max Distance (km)

Vs30 (m/s)

IMT

Depth (km)

Rake

Ref Distance for Spectrum (km)

SeismoMatch to PEER (.AT2)

Upload one or more SeismoMatch matched accelerogram (.txt) files — each with the Time(sec) / Acc(g) time history — and batch-convert them into PEER .AT2 strong-motion records (acceleration-only, units of g, with the time axis implied by DT). Each input produces one <name>.AT2; download them individually or all together as a .zip.

Upload SeismoMatch matched accelerograms (.txt) — select multiple files

Upload PEER .AT2 ground-motion files and download as plain text in sec acc format (fixed-point, no scientific notation).

Upload ground-motion records (.AT2) — select multiple files

Target DT (s)

Resample to target DT

Folder-organized TXT

Upload X/Y .AT2 pairs per ground motion and save them into a folder you choose — laid out as GM1/, GM2/, … (each holding its two components) plus top-level X/ and Y/ folders. Files are named RSN<tag>_FN (X / fault-normal) and RSN<tag>_FP (Y / fault-parallel). Pick sec acc or ChiChi text format. Leave a row blank to skip it.

Target DT (s)

Resample to target DT

Output format

sec acc ChiChi

PEER FORMAT

Upload an OpenQuake hazard-spectrum result (the lon,lat,<poe>~PGA,<poe>~SA(T)… CSV the engine exports for a UHS / hazard spectrum) and convert it to the PEER “User Defined Spectrum” CSV — a clean two-column T (s), Sa (g) table that reads straight into SeismoMatch and other target-spectrum tools. PGA maps to T = 0; each SA(T) column becomes a period point.

Upload OpenQuake hazard-spectrum results (.csv)

Spectrum title (header line in the PEER CSV)

Place PGA at T = 0.01 s (instead of 0)

Ground Motion Classification

Compute PGA, PGV, PGD, Central Period (T_c), and Normalized Velocity (PGV_n) with frequency and bandwidth classification.

Option 1 — Upload PEER .AT2 records

Upload ground-motion records (.AT2) — select multiple files

Option 2 — Upload Batch GM Excel (.xlsx)

Expected column order (no header row): station, record id, —, db, event, date, M_w, station name, V_S30, site class, R (km), PGA (g), PGV (cm/s), PGD (cm), …

Upload Batch GM workbook (.xlsx) — one or more files

Option 3 — Combine two horizontals (GeoMean & SRSS)

Upload a full record set (both horizontal components per RSN; the vertical is optional and ignored). Components are auto-paired by RSN — any PEER naming convention, including suffixes glued to the station code (e.g. GDLCN55W) and records with no vertical. The two horizontals are combined by geometric mean and by SRSS, then classified. Outputs two tables.

Upload PEER .AT2 records — the whole set (select multiple files)

Seed Motion — Time Histories & Response Spectrum

Upload a PEER .AT2 acceleration record to view its acceleration, velocity, and displacement time histories and its 5%-damped elastic response spectrum (the “seed-motion spectrum”), optionally overlaid on a target spectrum. The spectrum is computed with OpenSees (one SDOF oscillator per period, run as a transient) and can be exported as an OpenSees timeSeries Path — ready for responseSpectrumAnalysis — alongside an S_a-vs-T CSV. Use this as a visual screen of the seed motion before scaling or spectral matching; theory notes appear below the plot.

Upload PEER .AT2 acceleration record

Optional target-spectrum CSV (Period, Sa per row) — e.g. MCEₕ or a UHS export

Baseline-correct integration (linear detrend + 0.05 Hz high-pass)

Compute spectrum with OpenSees (SDOF transient via openseespy; falls back to FFT if unavailable)

Seismic Response-Spectrum Report

SpecMatReport

Generate a 5%-damped elastic response-spectrum overlay report. Upload a ground-motion acceleration record and a target spectrum; the record’s response spectrum is computed with OpenSees (one single-degree-of-freedom oscillator per period, run as a transient via openseespy) and overlaid on the target — no spectral matching is performed. Upload an optional Match record (a 2nd component) to also plot the geometric mean √(S_a,1·S_a,2) of the two, which is then compared against the target. The target accepts a simple period Sa table, an OpenQuake UHS (hazard_uhs) CSV, or a ShaCodeOverlay envelope CSV (an L1 or L2 export — its Envelope column is used). An optional site-response surface record can be plotted on the same axes. The overlaid spectra export as a tidy CSV and as OpenSees timeSeries Path snippets ready for responseSpectrumAnalysis.

Inputs

Seed record — required
PEER .AT2 or text (acceleration in g)

Match record — optional
2nd component (.AT2); adds the geometric mean √(S_a,1·S_a,2)

Target spectrum — required
period Sa table, OpenQuake UHS, or ShaCodeOverlay envelope CSV (L1/L2)

Surface record — optional
site-response output: .AT2/.txt or DEEPSOIL .xlsx

Report title — optional

Damping ζ

dt (s) — single-column text only

Compute with OpenSees (falls back to FFT)

Mean Spectra

Upload a suite of acceleration records (PEER .AT2 or text — ChiChi / sec acc / one accel per line) to compute their 5%-damped response spectra on a common period grid (0.01–10 s). Individual records plot as thin grey lines; the suite mean is the thick black line. The CSV download (period, every record, mean) can be re-used as a target spectrum in Spectral Matching.

The suite mean computed here is the mean matched spectrum at the bedrock (input-motion) level. Use the comparisons below to overlay it against the surface-level mean and the BSDS design spectrum.

Upload records (.AT2 or .txt — acceleration in g) — select the whole suite

Mean type

Axis scale

Damping

dt (s) — only for single-column text

Figure title — optional

BSDS Design Spectrum Comparison

Compute the mean spectra above, then upload a BSDS design spectrum data file to overlay it against the mean matched spectrum. The file is tab / space / comma separated with the columns Period(s) Acceleration(g) 2/3 Acceleration(g) (a non-numeric header row is skipped; the 2/3 column is optional).

Upload BSDS design spectrum (.txt)

Surface-Level Mean Spectrum Comparison

The mean above is the bedrock (input) mean matched spectrum. Upload the surface-level mean spectrum (e.g. the DEEPSOIL Mean Spectra CSV with a Period (s) column and a Mean (g) column) to overlay bedrock vs surface vs the BSDS design spectrum. Load the BSDS file in the section above first to include it in this plot.

Upload surface-level mean spectrum (.csv)

Fling Application Figure

Add a tectonic fling step to the fault-parallel (FP) component and compare FP, FP + fling, and FN — acceleration/velocity/displacement time histories and the 5%-damped response spectra (reproduces Fugro Fig 10.3-1). Fling is added to FP only; FN is shown for comparison. Controlling-fault defaults are for the West Valley Fault.

Upload FP (fault-parallel) .AT2

Upload FN (fault-normal) .AT2

Controlling fault

M (magnitude)

Rrup (km)

Dip (deg)

Dfault slip (m)

t₀ arrival (s)

Polarity (+1 / -1)

D_site (m) — optional

Baseline-correct each component (polynomial-on-displacement) before adding fling

Pulse / Non-Pulse Classification

Decide whether a near-fault record is pulse-like or non-pulse-like using the wavelet algorithm of Baker (2007) — the method our reference adopts (Shahi & Baker, 2011). The record is integrated to velocity, the largest velocity pulse is extracted with a db4 wavelet, and the Pulse Indicator (PI), pulse period T_p, and PGV give a ✅/❌ verdict. Test the fault-normal component (or rotate to FN first).

Upload acceleration record (.AT2 / .txt)

Label (optional)

PGV threshold (cm/s)

Linear-detrend the velocity (remove integration drift)

DEEPSOIL Results Extractor

Upload DEEPSOIL output Excel files to extract PGA, PGV, and PGD from Layer 1.

Upload DEEPSOIL output files (.xlsx) — select multiple files

Folder-organized TXT

Upload X/Y DEEPSOIL .xlsx pairs per ground motion and save the Layer 1 surface motion into a folder you choose — laid out as GM1/, GM2/, … (each holding its two components) plus top-level X/ and Y/ folders. Files are named RSN<tag>_FN (X / fault-normal) and RSN<tag>_FP (Y / fault-parallel). Pick sec acc or ChiChi text format. Leave a row blank to skip it.

Target DT (s)

Resample to target DT

Output format

sec acc ChiChi

DEEPSOIL to TXT

Upload DEEPSOIL .xlsx output files and download the Layer 1 surface motion as plain text in sec acc format (fixed-point, no scientific notation).

Upload DEEPSOIL output (.xlsx) — select multiple files

Folder-organized TXT

Upload X/Y DEEPSOIL .xlsx pairs per ground motion and save the Layer 1 surface motion into a folder you choose — laid out as GM1/, GM2/, … (each holding its two components) plus top-level X/ and Y/ folders. Files are named RSN<tag>_FN (X / fault-normal) and RSN<tag>_FP (Y / fault-parallel). Pick sec acc or ChiChi text format. Leave a row blank to skip it.

Target DT (s)

Resample to target DT

Output format

sec acc ChiChi

DEEPSOIL Mean Spectra

Upload the DEEPSOIL surface output workbooks (one per ground motion, e.g. all 11) to average their 5%-damped surface response spectra from the Layer 1 sheet. You get the mean spectrum on its own, the mean over the individual motions, and the full table as CSV.

Upload DEEPSOIL output files (.xlsx) — select all motions (e.g. 11)

Mean type

Axis scale

BSDS Design Spectrum Comparison

Compute the mean spectrum above, then upload a BSDS design spectrum data file to overlay it against the mean. The file is tab / space / comma separated with the columns Period(s) Acceleration(g) 2/3 Acceleration(g) (a non-numeric header row is skipped; the 2/3 column is optional).

Upload BSDS design spectrum (.txt)

Ground Motion Polar Plot

Upload two horizontal components (X and Y) of PEER AT2 input motion and/or DEEPSOIL surface output. Acceleration is double-integrated to displacement (cm) and visualized as the rotated PGD rose, displacement hodograph, compass-polar PGD, and the QuakeManager-style Polar Chart.

PEER Input (.AT2)

X-component AT2 (horizontal 1)

Y-component AT2 (horizontal 2)

DEEPSOIL Output (.xlsx)

X-component DEEPSOIL (Layer 1)

Y-component DEEPSOIL (Layer 1)

Azimuth step (deg): Baseline-correct displacement

Displacement Polar Chart

Double-integrates acceleration to displacement (cm) and renders the QuakeManager-style Polar Chart: POLAR_ENV (rotated peak-displacement envelope) and 2D_TRACE (particle-motion orbit). Upload up to 7 X/Y pairs — each pair can be PEER (.AT2) or DEEPSOIL (.xlsx).

Azimuth step (deg): Baseline-correct displacement

Displacement Orbit Compare

Compare the particle-motion displacement orbit (Disp 1 vs Disp 2, double-integrated from acceleration) across three processing stages — SEED (as-recorded), Match (spectrally matched), and Surface (site-response output) — side-by-side on a shared scale, with a combined overlay. Each input is an X/Y pair (PEER .AT2 or DEEPSOIL .xlsx). Upload one, two, or all three.

Baseline-correct displacement

Batch — auto-pair X/Y by station

Drop in all X-component (fault-normal, RSN…_FN) and all Y-component (fault-parallel, RSN…_FP) records at once. Files are paired automatically by their RSN<number> station tag, and one displacement orbit is plotted per station, each on its own auto-fit scale so weak and strong motions are both readable. PEER .AT2 or plain time accel .txt both work.

X components (Disp 1 / FN) — select multiple

Y components (Disp 2 / FP) — select multiple

Baseline-correct displacement

Batch Compare — Original vs Matched vs DEEPSOIL (auto-pair X/Y by station)

Drop in the Original, Matched and (optionally) DEEPSOIL surface record sets, each as an X-component (Disp 1) and Y-component (Disp 2) batch. Files are paired automatically by their RSN<number> station tag and, for every station, the Original (grey), Matched (red) and DEEPSOIL (green) orbits are overlaid on a shared per-station scale — so spectral-matching and site-response amplification are read directly off the orbit. Original/Matched accept PEER .AT2 or plain time accel .txt; DEEPSOIL accepts .xlsx. Provide any one, two, or all three sets.

Original X (Disp 1) — select multiple

Original Y (Disp 2) — select multiple

Matched X (Disp 1) — select multiple

Matched Y (Disp 2) — select multiple

DEEPSOIL X (Disp 1) — surface, select multiple

DEEPSOIL Y (Disp 2) — surface, select multiple

Baseline-correct displacement

Animated Orbit Plot

Watch the ground particle trace its displacement orbit over time. Upload one X/Y acceleration pair (PEER .AT2 or .txt); the records are double-integrated to displacement and the orbit (Disp X vs Disp Y) is animated with a growing trail and a moving particle. The ground acceleration and displacement time histories animate in sync below, with a time cursor that tracks the orbiting particle. Play / pause, scrub through time, and adjust the speed.

X component (.AT2 / .txt)

Y component (.AT2 / .txt)

Label (optional)

Baseline-correct displacement (0.05 Hz high-pass)

Corrected Ground Motion

Apply baseline correction to acceleration records and export the corrected motions. Correction is a linear detrend + 4th-order Butterworth high-pass at 0.05 Hz (zero-phase), the same scheme used by Displacement Orbit Compare — it strips the slow drift that otherwise corrupts integration, while preserving the record's shape and phase. Every record is corrected independently on its own series — there is no X/Y pairing and no cross-record coupling, so you can drop in X only, Y only, or both.

The six inputs are just for organising the output by role and component. Drop your Original, Matched and (optionally) DEEPSOIL records into the matching X / Y boxes — each file is corrected on its own. Original/Matched accept PEER .AT2 or plain time accel .txt; DEEPSOIL accepts .xlsx. For every record you get an uncorrected-vs-corrected comparison figure (acceleration and double-integrated displacement), and the corrected acceleration is exported as plain time accel .txt, bundled as a ZIP foldered by role and component.

Original X (Disp 1) — select multiple

Original Y (Disp 2) — select multiple

Matched X (Disp 1) — select multiple

Matched Y (Disp 2) — select multiple

DEEPSOIL X (Disp 1) — surface, select multiple

DEEPSOIL Y (Disp 2) — surface, select multiple

High-pass corner (Hz) Low-pass corner (Hz) Order

Defaults (0.05 Hz high-pass, 4th order, low-pass off) match Displacement Orbit Compare. Add a low-pass corner to apply a band-pass.

Corrected Ground Motion — Displacement Baseline (TEST)

An experimental sibling of Corrected Ground Motion that corrects in the displacement domain instead of high-passing the acceleration. Each record is double-integrated to displacement, a low-order polynomial is fit to the drift, and its second derivative is subtracted from the acceleration (polynomial baseline correction). The corrected acceleration then double-integrates — with no Orbit-Compare toggle — to a near-zero-drift displacement, so the orbit tends to close on its own. PGA and the spectral match are largely preserved (only a smooth, very-low-frequency term is removed).

This module is for A/B testing and does not affect the production Corrected Ground Motion module. Each file is corrected independently on its own series (no X/Y pairing). The displacement panel below uses plain double-integration (toggle OFF) so you can see directly whether the corrected record closes the orbit. The corrected acceleration is exported as both .txt (ChiChi npts dt + t acc) and PEER .AT2, bundled as a ZIP foldered by role and component.

Original X (Disp 1) — select multiple

Original Y (Disp 2) — select multiple

Matched X (Disp 1) — select multiple

Matched Y (Disp 2) — select multiple

DEEPSOIL X (Disp 1) — surface, select multiple

DEEPSOIL Y (Disp 2) — surface, select multiple

Polynomial order

GM Outcrop vs Surface

Compare each ground motion's peak values — PGA (g), PGV (cm/s) and PGD (cm) — between the outcrop (bedrock input) record and the surface (site-response output) record. Upload all bedrock motions in one bucket and all surface motions in the other; files are paired automatically by their RSN<number> station tag, and a median row is added. PEER .AT2, SeismoMatch .AT2, DEEPSOIL .xlsx, or plain time accel .txt all work.

Outcrop / bedrock motions — select multiple

Surface motions — select multiple

Title / level label (optional) Baseline-correct PGV/PGD

Smooth Spectra Compare

Overlay the smoothed bedrock (outcrop), surface (site-response) and BSDS code design spectra on one 5%-damped plot. Reads the Period (s), Sa (g), ⅔ Sa (g) columns from each file (comma, tab, or space separated, header row optional) and reports the surface/bedrock amplification and surface-vs-code ratios.

Input format requirements

Bedrock smooth CSV

Smoothed bedrock/outcrop spectrum — columns Period (s), Sa (g), ⅔ Sa (g), comma-separated, header row.

Period (s),Sa (g),2/3 Sa (g)
0.0000,0.612321,0.408214
0.1300,1.103667,0.735778
1.0000,0.733134,0.488756
8.0000,0.091642,0.061094

Surface smooth CSV

Smoothed surface (site-response) spectrum — same three-column format as bedrock.

Period (s),Sa (g),2/3 Sa (g)
0.0000,0.405884,0.270589
0.3900,0.466234,0.310823
1.0000,0.466234,0.310823
8.0000,0.112948,0.075298

BSDS code TXT

BSDS Level II design spectrum — Period(s), Acceleration(g), ⅔ Acceleration(g), tab- or space-separated.

Period(s)  Acceleration(g)  2/3 Acceleration(g)
0.0000  0.470000  0.313333
0.2300  0.966000  0.644000
1.0000  0.966000  0.644000
8.0000  0.135000  0.090000

Bedrock smooth spectrum (Period, Sa, ⅔ Sa CSV)

Surface smooth spectrum (Period, Sa, ⅔ Sa CSV)

BSDS code design spectrum (Period, Acceleration, ⅔ TXT)

Plot title

ShaCodeOverlay

Overlay the deterministic (DSHA), probabilistic (PSHA) and Code (BSDS) design response spectra on one 5%-damped log-log plot, with their ⅔ variants. Overlay just plots the uploaded spectra as-is — no processing. Process then generates the Level‑2 envelope (the point-wise maximum of the full spectra). Upload a PSHA spectrum and a Code design spectrum; DSHA is optional.

Input format requirements

DSHA spectrum CSV · optional

Deterministic (DSHA) response spectrum — two columns Period (s), Acceleration (g), comma-separated, with a header row. Periods may be sparse. The ⅔ curve is computed.

Period(s),Acceleration(g)
0,0.235
0.1,0.402
0.2,0.486
0.5,0.470
1,0.300
3,0.090

PSHA / UHS spectrum CSV

Probabilistic (PSHA) uniform-hazard spectrum — same two-column format as DSHA (e.g. a UHS export). One Period, Sa pair per row.

Period(s),Acceleration(g)
0,0.228988
0.1,0.394983
0.2,0.498632
0.5,0.442310
1,0.266237
3,0.082794

Code (BSDS) design TXT

Code design spectrum — three columns Period (s), Acceleration (g), ⅔ Acceleration (g), tab- or space-separated, with a header row.

Period(s)  Acceleration(g)  2/3 Acceleration(g)
0.0000  0.450000  0.300000
0.0100  0.499995  0.333330
0.1300  1.056000  0.704000
1.0000  0.640000  0.426667
8.0000  0.080000  0.053333

DSHA spectrum — optional (Period(s), Acceleration(g) CSV)

PSHA spectrum (Period(s), Acceleration(g) CSV)

Code design spectrum (Period(s) Acceleration(g) 2/3 Acceleration(g) TXT)

Plot title

SurCodeOverlay

Overlay the surface mean spectra (DEEPSOIL, X and Y) against the Code (BSDS) design spectrum and its ⅔ variant. Each mean is idealised into a DPWH-BSDS site-specific design spectrum (the smoothed curve), exactly as the seismicpy — DPWH BSDS Site-Specific Spectrum tool does: with F_pga=F_a=F_v=1, the anchors are read straight off the mean — pga = mean at the first period, S_s = mean at 0.2 s, S₁ = mean at 1.0 s. The envelope is the point-wise higher of the ⅔ BSDS and the smoothed curve, computed separately for X and Y.

Input format requirements

Mean spectrum X CSV

DEEPSOIL surface mean spectrum (X) — a Period (s) column and a Mean (g) column (the arithmetic mean). Extra per-record columns are ignored; the Mean (g) column is found by name.

Period (s),...,Mean (g),...
0.010000,...,0.389427,...
0.200000,...,0.412506,...
1.000000,...,0.847752,...

Mean spectrum Y CSV

DEEPSOIL surface mean spectrum (Y) — same format as the X file (a Period (s) column and a Mean (g) column).

Period (s),...,Mean (g),...
0.010000,...,0.399419,...
0.200000,...,0.412506,...
1.000000,...,0.847752,...

Code (BSDS) design TXT

BSDS Level-II design spectrum — two or three columns Period (s), Acceleration (g), ⅔ Acceleration (g), tab/space/comma separated, header skipped. The ⅔ column is optional (else derived).

Period(s)  Acceleration(g)  2/3 Acceleration(g)
0.0000  0.470000  0.313333
0.2000  0.966000  0.644000
1.0000  0.966000  0.644000
8.0000  0.135000  0.090000

Mean spectrum X (DEEPSOIL surface CSV — Period (s), Mean (g))

Mean spectrum Y (DEEPSOIL surface CSV — Period (s), Mean (g))

Code design spectrum (Period(s) Acceleration(g) 2/3 Acceleration(g) TXT)

Plot title

Max period (s)

Surface X/Y Combine — GeoMean / SRSS

Combine two DEEPSOIL surface mean-spectrum CSVs (X and Y directions) into a single horizontal spectrum by geometric mean and SRSS, read off PGA / S_a(0.2 s) / S_a(1.0 s) in a table, and optionally overlay a BSDS design spectrum to compare. Inputs are the mean-spectrum CSVs (a Period (s) column plus Mean (g) / Geometric Mean (g) summary columns) — the same files the SurCodeOverlay and Mean Spectra modules read.

Surface Mean Spectrum — X (.csv)

Period (s), …, Mean (g) …

Surface Mean Spectrum — Y (.csv)

Period (s), …, Mean (g) …

Direction spectrum column

BSDS design spectrum — optional (Period, S_a, [⅔])

Upload a BSDS curve to compare

SpecCombine — Two-Component Spectrum Combination

Combine the response spectra of the two horizontal components of a ground motion four ways: SRSS (square root of the sum of squares), the as-recorded geometric mean, and the orientation-independent RotD50 (median) and RotD100 (maximum) measures of Boore (2010). RotD rotates the pair through all non-redundant azimuths (0–179°, 1° step) at every period and takes the peak SDOF oscillator response of the rotated motion — so it needs the two acceleration time histories, not precomputed spectra. Components are resampled to a common time step and trimmed to a common length before combining; spectra are computed at 100 log-spaced periods from 0.01 to 10 s.

Upload H1 (first horizontal component) — .AT2 / .txt

Upload H2 (second horizontal component) — .AT2 / .txt

Damping (%)

dt (s) — single-column .txt only

Change Log

PSHA Tool by Albert Pamonag

v3.4.2 (2026-07-09)

UHS PEER export → QAQC log: Clicking Download PEER Format on the Uniform Hazard Spectrum result now writes a QAQC audit-log entry recording the exported spectrum — its title, filename, period count and PGA (T=0) — so PEER-format exports are traceable in the QAQC log alongside the other analyses.

v3.4.1 (2026-07-09)

UHS Generator — Download PEER Format: The Uniform Hazard Spectrum result now offers a Download PEER Format button alongside CSV and SeismoMatch Input — exports the generated spectrum as a PEER “User Defined Spectrum” CSV (title line, then T (s), Sa (g) rows, PGA at T = 0), the same layout produced by the PEER FORMAT module and read by SeismoMatch and other target-spectrum tools.

v3.4.0 (2026-07-09)

PEER FORMAT: New Ground-Motion conversion module that turns an OpenQuake hazard-spectrum export (one row per site, columns lon,lat,<poe>~PGA,<poe>~SA(T)…, with the leading #… metadata line) into the PEER “User Defined Spectrum” CSV — the two-column T (s), Sa (g) layout SeismoMatch and other target-spectrum tools read. PGA maps to T = 0 (optionally 0.01 s) and each SA(T) column becomes a period point. Auto-detects the header past the comment line, groups by probability of exceedance and reports the equivalent return period (from investigation_time), and handles multi-site / multi-PoE exports — one spectrum each, plotted together, with per-spectrum PEER-CSV downloads plus a single .zip of all.

v3.3.0 (2026-07-04)

Surface X/Y Combine — GeoMean / SRSS: New Spectra module that combines two DEEPSOIL surface mean-spectrum CSVs (X and Y directions) into a single horizontal spectrum by geometric mean and SRSS. Pick the direction column (Mean (g) or Geometric Mean (g)); Y is log-linearly interpolated onto X's period grid before combining. Reads off the combined acceleration at T = 0 (PGA), 0.2 s and 1.0 s into a Combined design-accelerations table (GeoMean / SRSS rows), with a per-direction spectral-values table alongside; overlays X, Y, GeoMean and SRSS on one log-period plot, and — when a BSDS design spectrum (Period, S_a, [⅔]) is supplied — adds the BSDS and ⅔-BSDS curves plus GeoMean/BSDS and SRSS/BSDS demand ratios to the table for direct comparison. Exports the combined result as a wide CSV / Excel, plus clean two-column Period (s), Sa (g) spectra per combination (GeoMean / SRSS) that read straight back into the BSDS slot and other Period/S_a spectrum modules.

v3.2.0 (2026-07-04)

SeismoMatch → RSseismic: New Ground-Motion conversion module that turns SeismoMatch matched-accelerogram records (time / acceleration text, accel in g) directly into the RSseismic text input format — the same one-line NPTS DT header + two-column time acceleration (g) layout as QuakeManager → RSseismic — with no intermediate .AT2 step. Auto-detects the SeismoMatch / ChiChi / 2-column layouts via the shared seed-record reader, batch upload, optional resample to a target DT (off by default to preserve native NPTS/DT), and per-file download or a single .zip of all *_chichi_format.txt outputs.

v3.1.0 (2026-07-04)

GM Classification — GeoMean / SRSS: New “Option 3” on the Ground Motion Classification page that combines the two horizontal components of each record — auto-paired by RSN (any PEER naming, including suffixes glued to the station code and vertical-less records) — by geometric mean and SRSS, then classifies each combined pair with the existing T_c / PGV_n scheme. Renders two tables, a combined CSV download (with a Combination column), and sortable full views; records with fewer or more than two horizontals are reported separately.

v3.0.1 (2026-07-03)

Plots: All interactive plots now keep a white plot interior in both themes for easy reading — grid lines stay dark inside the plot while axis titles, tick labels, and annotations on the surrounding margin still follow the light/dark theme. Custom colored axes (e.g. the amber Arias build-up axis) are preserved, and legends pinned inside the plot area use dark text on a translucent white backing.

v3.0.0 (2026-07-03)

SpecCombine: New Spectra & Matching module that combines the two horizontal components of a ground motion into four spectra: SRSS, the as-recorded geometric mean, and the orientation-independent RotD50 / RotD100 measures (Boore 2010) — the pair is rotated through all non-redundant azimuths (0–179°, 1° step) at every period and the peak SDOF response taken per azimuth. Four interactive plots (one per combination, each overlaying the H1/H2 component spectra), peak metrics, and CSV / Excel export. Pure-numpy frequency-domain SDOF engine with a convex-hull reduction of the oscillator orbit, so a 100-period × 180-azimuth run takes under a second.
UI: Major redesign — a dark, earthquake-themed “seismic observatory” look with a magma-orange accent, seismogram-paper backdrop, animated waveform hero, and a wide-screen layout (content now up to 1760 px). A light / dark toggle in the top bar remembers your choice; all modules and plots follow the selected theme.

v2.19.0 (2026-06-25)

Arias Intensity Trim: New Ground-Motion module that trims PEER .AT2 records to their significant-duration window from the Arias-intensity (Husid) build-up between two thresholds (default 5–95 % → D_5–95). The low-amplitude lead-in and tail are removed; the header is preserved (only NPTS updated) and DT is unchanged, so the output is the same .AT2 format, trimmed. Reports NPTS/duration before→after, the trim window, D_5–95, and Arias intensity I_a, and draws a before/after plot per record (original acceleration with the Arias window shaded and the Husid build-up, beside the trimmed result); supports batch trimming with a per-file or zip download.

v2.18.1 (2026-06-24)

SurCodeOverlay: Added a confirmation check plot overlaying the re-smoothed envelope, ⅔ BSDS, BSDS, and the mean (X and Y) on one figure with a clickable legend — click a series to toggle it, double-click to isolate.

v2.18.0 (2026-06-24)

SurCodeOverlay: Moved into the Spectra & Matching group beside ShaCodeOverlay. Added a re-smoothed envelope step — each per-direction envelope is idealised again with the same DPWH-BSDS site-specific process (anchors read off the envelope: pga at the first period, S_s at 0.2 s, S₁ at 1.0 s), plotted over the envelope it came from, with a downloadable CSV for the X and Y re-smoothed envelopes

v2.17.0 (2026-06-24)

SurCodeOverlay: New Ground-Motion module overlaying the DEEPSOIL surface mean spectra (X and Y) against the BSDS code design spectrum and its ⅔ variant. Each mean is idealised into a DPWH-BSDS site-specific design spectrum (the smoothed curve) the same way as the seismicpy site-specific tool — F_pga=F_a=F_v=1, anchored on pga (mean at the first period), S_s (mean at 0.2 s) and S₁ (mean at 1.0 s). The per-direction envelope is the point-wise maximum of the ⅔ BSDS floor and the smoothed curve. Plots the X graph, Y graph, combined X&Y, and the X / Y envelopes alone, with a downloadable CSV for each (and a download-all)

v2.16.1 (2026-06-24)

Dashboard: credit line now reads “developed by Albert Pamonag and Camille Pajarillaga.”
Housekeeping: trimmed the repository to the deployed app — removed superseded standalone scripts and orphaned page templates, and moved research notebooks/data out of the app repo. No change to module behavior.

v2.16.0 (2026-06-24)

Welcome dashboard: Redesigned home page — a new gradient hero with the tool description, and a live module search that filters cards by name and description as you type (empty groups collapse). The modules are reorganized into clearer groups with per-section counts: Seismic Hazard, Source Model, and five Ground Motion sub-groups (Records & Conversion, Spectra & Matching, Near-Fault & Baseline, Orbit & Polar, Site Response)

v2.15.0 (2026-06-23)

Animated Orbit Plot: New Ground-Motion module that animates the particle-motion displacement orbit of a single X/Y pair. The records are double-integrated to displacement and the orbit (Disp X vs Disp Y) plays back as a moving particle with a growing trail over the faint full orbit and a peak-displacement marker. The ground acceleration and displacement time histories (X and Y) animate in sync underneath, with a time cursor and value dots that track the orbiting particle. Interactive controls — play / pause, a time scrubber, a 0.25–4× speed slider, and a loop toggle — plus PGD_X/PGD_Y/peak |u| metrics, a PNG frame export, and a CSV (time, acc X/Y, disp X/Y). Optional baseline correction; accepts PEER .AT2 or .txt

v2.14.0 (2026-06-23)

Pulse / Non-Pulse Classification: New Ground-Motion module that decides whether a near-fault record is pulse-like (forward directivity) or non-pulse-like using the wavelet algorithm of Baker (2007) — the method adopted in Shahi & Baker (2011). The acceleration is integrated to velocity, the largest velocity pulse is extracted with a db4 wavelet, and the Pulse Indicator PI = 1/(1+exp(−23.3+14.6·R_PGV+20.5·R_E)) is computed from the residual PGV and energy ratios. A record is flagged pulse-like only when PI ≥ 0.85, PGV > 30 cm/s, and the pulse arrives early. Reports PI, pulse period T_p, and PGV with a verdict, plots the original / extracted-pulse / residual velocities, and downloads a CSV. Test the fault-normal component (PEER .AT2 or .txt)

v2.13.0 (2026-06-23)

Smooth Spectra Compare: New Ground-Motion module that overlays the smoothed bedrock (outcrop), surface (site-response), and BSDS code design spectra on one 5%-damped plot. Reads the Period (s), Sa (g), ⅔ Sa (g) columns from each file (comma, tab, or space separated), toggles between full S_a / ⅔ S_a and log / linear axes, reports surface/bedrock amplification (peak and max) plus the share of periods where the surface demand reaches the code spectrum, and downloads a union-grid CSV with the Surface/Bedrock and Surface/BSDS ratios

v2.12.0 (2026-06-23)

QuakeManager → RSseismic: New Ground-Motion module that converts QuakeManager PEER .AT2 acceleration records into the RSseismic text input format — a one-line NPTS DT header followed by two columns of time acceleration (g) (the ChiChi-style layout RSseismic reads). Batch upload, optional resample to a target DT (off by default to preserve native NPTS/DT), and per-file or download-all of the *_chichi_format.txt output

v2.11.0 (2026-06-12)

Site Location selector: Declustering, Depth & Nodal, Focal Mechanisms, and SSM Visualizer now share one Site Location panel — pick a saved site from the Site dropdown and the latitude/longitude fill in on every page at once, so the site follows you across modules. Switch to Custom coordinates… to type values, save the current coordinates as a named site, or delete one. Sites persist in the browser between sessions, and the Focal fault list reloads automatically when the site moves

v2.10.0 (2026-06-10)

Focal Mechanisms: New interactive Mapbox map per fault — fault trace, dipping-plane surface projection, site and assumed-epicentre markers, labelled shortest-distance line to the trace, epicentre→site path, strike direction guide, and the θ strike-to-azimuth angle drawn as a yellow arc at the epicentre. Click the trace for strike/dip/rake, depths, R_RUP/R_JB/R_EPI and θ; legend overlay and PNG download included

v2.9.0 (2026-06-10)

Focal Mechanisms: Directivity table is now self-explaining — every row is clickable and expands a derivation box showing the formula with the actual numbers substituted (e.g. X = s/L = 39.2/78.4 = 0.50, the θ folding chain, taper rules). The yellow hatch now marks all governing directivity-effect values: θ, X = s/L, and the governing predictor (X·cos θ capped for strike-slip, Y·cos φ for dip-slip)

v2.8.0 (2026-06-10)

Focal Mechanisms: Directivity X is now computed from geometry instead of a fixed 0.5 — s (along-strike rupture length between the mid-trace epicentre and the trace point closest to the site), X = s/L fraction rupturing toward the site, plus the conservative far-end-nucleation bound X_max with its capped X_max·cos θ predictor. The θ strike-to-azimuth row is highlighted with a yellow hatch
SSM Visualizer: Gridded-seismicity XML files start unchecked in the file list (opt in to load them)

v2.7.0 (2026-06-10)

SSM Visualizer: Interactive Mapbox map upgraded to analysis grade — color faults by tectonic region / Mmax / distance-to-site with a live legend, line width scaled by Mmax, 50/100/200/300 km labelled distance rings, hover highlight, rich click popups (dip, rake, depths, trace length, min distance) with a labelled site–to–source shortest-distance line, fault-name labels, basemap switcher (Satellite Streets / Streets / Outdoors / Light / Dark), 3D terrain toggle, and table→map locate: click any row in the source tables to fly to that source. Backend GeoJSON now carries dip, rake, depths, trace length, and vertex-based distance per source

v2.6.0 (2026-06-10)

Focal Mechanisms: New Directivity Parameters results table — θ strike-to-azimuth angle between the fault strike and the epicentre–site path (folded to 0–90°, nucleation unknown), with cos θ, fault trace length L, and the Somerville et al. (1997) predictors X·cos θ (strike-slip, incl. the Abrahamson 2000 cap at 0.4) and φ/Y·cos φ (dip-slip), the governing predictor per faulting style, and the Abrahamson (2000) distance/magnitude applicability tapers. θ also shown as a key-metric chip

v2.5.0 (2026-06-10)

Spectral Matching: New module that matches a seed acceleration record (PEER .AT2 or text — ChiChi, sec acc, or single-column) to a target 5%-damped response spectrum via frequency-domain iteration, preserving the original phase. Produces the seed and spectrally-matched acceleration time histories and a target/seed/matched spectra comparison (reproduces Fig A-34), reports mean/max match misfit over the matching band, and downloads the matched record as .AT2 or text

v2.4.0 (2026-06-09)

Removed: the Deaggregation module

v2.3.0 (2026-06-09)

Displacement Orbit Compare: New module to compare the particle-motion displacement orbit (Disp 1 vs Disp 2) across three processing stages — SEED (as-recorded), Match (spectrally matched), and Surface (site-response output) — as side-by-side panels on a shared scale plus a combined overlay, with per-motion PGD₁/PGD₂/PGD_RotD100 metrics and CSV download. Each input is an X/Y pair (PEER .AT2 or DEEPSOIL .xlsx)
Removed: the DSHA (Deterministic Seismic Hazard Analysis) module

v2.2.0 (2026-06-08)

BSDS Curve: New module that plots a BSDS design response spectrum from an uploaded data file (Period(s), Acceleration(g), optional 2/3 Acceleration(g); tab/space/comma separated, header ignored). Shows the design Sa and 2/3 Sa curves with derived parameters (A_s, S_DS, S_D1, T_s, T₀), T₀/T_s reference guides, an axis-scale toggle (linear / semilog / log–log), and CSV download

v2.1.0 (2026-06-08)

DEEPSOIL Mean Spectra: New module that averages the 5%-damped surface response spectra (Layer 1) across a suite of DEEPSOIL output workbooks (e.g. 11 motions). Spectra are placed on a common period grid (log-log interpolated when needed); switch the mean between arithmetic (average) and geometric (lognormal). Two plots — the mean on its own, and the mean as a thick line over the individual spectra drawn as thin grey lines — plus a CSV download with period, every individual spectrum, mean, geometric mean, standard deviation, and lognormal sigma

v2.0.0 (2026-04-05)

Declustering: 3 windowing methods (Gardner-Knopoff, Grünthal, Uhrhammer) with checkboxes, distance-time window comparison plot, per-method before/after magnitude-time scatter, per-method CSV download
Completeness: Stepp (1972) automated analysis with bilinear fit, manual completeness table override, "both" mode overlay, output for whole catalogue + shallow/mid/deep depth classes, viridis colormap
Catalogue Convert: Upload CSV/XLSX, auto-detect format (USGS, PHIVOLCS Excel, generic), convert to HMTK tab-separated format with download
Catalogue Check: 4 analysis plots (map, depth histogram, mag-time scatter, mag-time density) without converting to HMTK first
Catalogue QAQC: Duplicate detection (sliding window), magnitude consistency checks, temporal gap analysis with events-per-year bar chart
Max Magnitude: Observed Mmax estimation with cumulative moment release plot
Depth & Nodal: Depth distribution histogram, depth PMF table, auto-generated OpenQuake hypoDepthDist XML snippet
SSM Visualizer: Parse NRML 0.5 XML source models (SimpleFault, ComplexFault, MultiPoint), map with Philippines coastline, checkbox per-file selection, Mapbox interactive map with fault popups, 300km radius, per-TRT source tables
GMPE Comparison: PHIVOLCS-GEM-Oct2020 reference with 7 plots: 3 per-TRT attenuation curves (Active Shallow Crust, Subduction Interface, Intra-Slab), logic tree weighted comparison, combined envelope, response spectrum (0-3s), per-TRT only spectrum
Focal Mechanisms: Per-fault analysis from SSM within 300km: professional cross-section diagram (R_RUP, R_JB, R_EPI, R_HYPO), 3D Plotly fault plane with distance lines, 28-row parameter table with descriptions, GMPE requirements table (11 GMPEs), OpenQuake nodalPlaneDist XML
Light/Dark theme: Toggle button in sidebar, persists via localStorage, Plotly charts adapt to theme
OpenQuake HMTK localized: 12 tutorial notebooks extracted from OpenQuake with local dependencies (no openquake.engine needed for notebooks 1-8)
Mapbox default: Satellite-streets style, API key configured

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
QAQC audit log with checklist
Flask + vanilla JS frontend (lightweight)
Deployed at psha.apeconsultancy.net