README.md
In gmsp: Ground Motion Signal Processing

gmsp

Ground Motion Signal Processing

gmsp implements STFT-based processing of strong-motion time series: time-grid regularisation via monotone-Hermite interpolation, STFT-window and anti-alias-resampling strategy selection, edge tapering of low-amplitude pre/post segments, and frequency-domain integration and differentiation. A single input (acceleration, velocity, or displacement) is mapped into a consistent (AT, VT, DT) triplet under one chosen Fmax analysis bandwidth.

On top of that pipeline the package provides

IMF decomposition through one of three engines — EMD, EEMD, or VMD (default) — with optional band-rule mode filtering and per-IMF metrics (center frequency, bandwidth, relative energy);
elastic SDOF domain-normalised spectra (PSA / PSV / SD) from the independent acceleration / velocity / displacement rows of canonical TSL through TSL2PS(), by exact state-space integration of the 2D oscillator equation with expm(A·dt) over a user-supplied period grid, including optional D50 and D100 horizontal spectra;
a per-record table of intensity measures from a long TSL input — PGA / PGV / PGD, RMS, zero-crossings, Arias intensity and its positive / negative variants AI / AIu / AId, three significant- duration measures D5–95 / D5–75 / D20–80, CAV and CAV5, mean period Tm, and the derived indices EPI and PDI.

A provider-format indexing layer parses six raw record formats — PEER NGA-W2 AT2, CESMD V2 / V2c, NWZ V2A, Geological Survey of Canada TR, Peruvian and Costa Rican AC variants (ACA / LIS), and generic two-column ASCII — normalises the three physical components to canonical mm, classifies them as H1 / H2 / UP, equalises NP across channels, and writes a per-record CSV/JSON pair under <recordsDir>/<OwnerID>/<EventID>/<StationID>/raw/. The same layer builds per-owner index CSVs (file / record / intensity tables) and joins them with event and station metadata into an in-memory master record data.table keyed at (RecordID, DIR). Every function that touches disk takes its base path as a required argument; the package does not assume a specific filesystem root.

Requires R >= 4.1.0.

# Stable release:
install.packages("gmsp")

# Development version:
remotes::install_github("averriK/gmsp")

Signal-processing core: AT2TS(), VT2TS(), DT2TS(), TS2IMF() for single-series IMF decomposition, TSL2PS() for canonical TSL response spectra including D50, getIntensity().

Indexing layer: readAT2(), readV2(), readV2A(), readAC(), readTR(), readTwoCol(), parseRecord(), mapComponents(), alignComponents(), extractRecord(), archiveRawOwner(), buildRawFileTable(), buildRawRecordTable(), buildRawIntensityTable(), selectRecords(), writeSelection(), readAT(), getRawIntensities(), auditSite(), auditDistances(), auditParsers().

Project pipeline wrappers: runSelect(), runGMSP(), runProcess(), runTrim(), runIMF(), runPSA(), runPlot(), runMatch(), and runExport() execute the installed JSON-driven pipeline runners from a project root.

Full reference: help(package = "gmsp") or https://averriK.github.io/gmsp/reference/.

R (>= 4.1.0).

Imports: data.table, digest, EMD, expm, hht, jsonlite, openssl, pracma, purrr, seewave, signal, spectral, stats, stringr, utils, VMDecomp.

Suggests: knitr, rmarkdown, testthat (>= 3.0.0).

Six vignettes ship with the package:

vignette("gmsp-quickstart",    package = "gmsp")  # runnable hello world
vignette("signal-processing",  package = "gmsp")  # AT2TS / VT2TS / DT2TS math
vignette("imfs",               package = "gmsp")  # TS2IMF (EMD / EEMD / VMD)
vignette("spectra",            package = "gmsp")  # TSL2PS elastic SDOF spectra
vignette("intensity-measures", package = "gmsp")  # getIntensity output
vignette("database",           package = "gmsp")  # provider-format indexing

Rendered documentation: https://averriK.github.io/gmsp/.