Processing Stream Options

Rotate Seismograms

This option rotates the three-component traces in the stream to either the Great Arc Circle (GAC) or a user-defined angle and inclination.

type: Defines the rotation transformation.
- NE->RT: Rotates North and East components to Radial and Transverse.
- RT->NE: Rotates Radial and Transverse components back to North and East.
- ZNE->LQT: Rotates from a left-handed Z, North, East system to an LQT (ray-based, right-handed) coordinate system.
- LQT->ZNE: Rotates from an LQT system back to a left-handed Z, North, East system.
method: Specifies the rotation method.
- GAC: Rotates according to the Great Arc Circle. Requires event metadata.
- FREE: Rotates to a user-defined angle and inclination (used for LQT transformations).
angle (float) – The back azimuth from station to source in degrees.
inclination (float). Inclination of the ray at the station in degrees. Only necessary for three component rotations.

Analysis:
  process_1:
    name: 'rotate'
    type: 'NE->RT'
    method: 'GAC'
    angle: 30.0
    inclination: 0.0

Performs cross-correlation between waveforms.

mode: Defines how the cross-correlation is computed, following the NumPy correlate method:
- full: Returns the complete cross-correlation function. Includes all shifts, even partial overlaps. Best if you want to scan the entire signal.
- valid: Returns only correlation values where the signals fully overlap. Safer when you want to avoid edge effects.
- same: Returns output of the same length as the input data, centered around zero lag.
normalize: Specifies how traces are normalized before correlation.
- full: Uses zero-normalized cross-correlation (ZNCC). Each point is normalized based on local signal energy and optional demeaning. This provides a correlation coefficient between -1 and 1 and is the most statistically meaningful
- naive:Normalizes both signals by their global standard deviation. Quicker but may introduce bias if signals have amplitude variation.
- none: No normalization is applied. Raw amplitudes are used, which may be sensitive to trace scaling or noise.
reference_idx: Index of the trace to use as the reference for correlation (typically one of the traces in the stream).
strict: If True, enforces strict alignment and compatibility between trace lengths and sampling rates.

Analysis:
  process_1:
    name: 'cross_correlate'
    mode: 'full'
    normalize: 'full'
    reference_idx: 0
    strict: True

Stacks multiple traces using a specified method.

method: Specifies the stacking method:
- linear: Simple arithmetic mean across traces.
- pw: Phase-weighted stacking, emphasizing coherent phase information. Order 1 is the parameter of this method. Recommended 1.
- root: nth-root stack
order: The exponent applied in phase-weighted stacking. A higher value gives stronger weighting to coherent signals.

  process_1:
    name: 'stack'
    method: 'pw'
    order: 1