Skip to content

Signal Shape Comparison

Purpose: compare real seismic/VLF observations with simulation-derived signals before training larger models.

Run:

./scripts/compare-signal-shapes.sh

Outputs:

  • *.signal_shape_series.csv - per-series time-domain and PSD metrics
  • *.signal_shape_pairs.csv - pairwise normalized distances and metric deltas

Series currently supported:

  • normalized INGV-like event CSVs binned into seismic energy traces
  • Cumiana VLF spectrogram JPGs reduced to column-intensity traces
  • *.piezo.csv reduced to the synthetic VLF analogue trace
  • *.avalanche_signal.csv reduced to the direct seismic analogue trace

Metrics include distribution shape, burstiness, lag-1 autocorrelation, PSD slope, spectral centroid, rolloff, and low/mid/high power ratios.

Pairwise normalized_distance uses dimensionless shape and PSD-ratio metrics. Absolute amplitude, sample count, and duration are still reported as deltas but are not included in that distance.

See Simulation Time Scale before interpreting PSD metrics.

Interpretation rules:

  • compare seismic event traces against direct avalanche traces
  • compare VLF image traces against piezo traces
  • do not compare raw physical frequencies across modalities without a declared time-scale mapping
  • treat distances as tuning diagnostics, not validation of predictive power