SpecMod¶

A Python toolbox for processing and modelling seismic spectra: cut a window, estimate its spectrum, decide which part of it is above the noise, and fit a source model to that band.

Alpha, pre-1.0 — pin an exact version for anything you publish

SpecMod is being rebuilt in the open, so treat everything here as provisional until the API settles at 1.0:

Names and signatures move between 0.x releases, without a deprecation cycle. Breaking changes land in minor bumps by design — that is what 0.x is for, and the alternative is a deprecation shim on an API that is still being worked out.
Some numbers still move too. The modern layers (specmod.config, specmod.core, specmod.transforms, specmod.picks, specmod.fitting) are built and tested against golden references; the modules that have not been reached yet carry pre-refactor behaviour, and a fix there can change a result. Changes that move a published number are called out in the changelog.
Pin an exact version for anything you intend to publish, and keep the configuration stamp that every output carries. Together they are what make a run reproducible while the package underneath is still moving.

What will not change silently: the units conventions and the Parseval contract are pinned by tests, and the golden references fail loudly rather than drifting. The roadmap says what has shipped, in which version, and what 1.0 will mean.

import specmod.preprocess as pre
from specmod.pipeline import spectrum_set_from_streams
from specmod.fitting import FitSpectra

stream = pre.with_picks(stream, "event.xml")
signal = pre.s_window(stream, rafp=0.8, tafs=20)
noise = pre.get_noise_p(stream, signal)

spectra = spectrum_set_from_streams(signal, noise)
fits = FitSpectra(spectra)
fits.fit_spectra()
print(fits.table[["id", "llpsp", "fc", "ts"]])

Where to go¶

Getting started: Install it, run one event end to end with the tutorial, and — if you have code written against 0.1 — find out what moved.
Guides: What each stage does and why, and where the conventions are stated: the amplitude convention, the Parseval contract, and the moment and magnitude equations.
API reference: Every public object. specmod.api is the narrower, more stable subset to import from if you are building on this.
Working on SpecMod: The roadmap, the developer guide, how this site is built, and how a merged commit becomes a release.

Two things worth knowing early¶

Units are typed. A spectrum carries its ground-motion domain and amplitude convention as attributes. Converting between them is a method that returns a new spectrum, so a moment computed from the wrong domain is a type error rather than a wrong number.

Fit in the units the sensor recorded. Integrating to displacement implicitly low-passes and differentiating to acceleration amplifies high-frequency noise, so the record to fit is the one that was measured. The model carries a motion factor, so the plateau it reports is the displacement one either way.