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Source delay statics estimates a static time correction for each source location by picking the first-break arrival on the minimum-offset stack sorted by source. For each source the pick time is compared to a reference alignment time. The difference, after removing the expected moveout contribution at the picked offset using a replacement velocity, gives the source static shift. This approach is effective for correcting source-side near-surface delays on land 2D and 3D surveys without requiring a full uphole or refraction survey.
The module operates interactively. Select a source location on the map, inspect the minimum-offset stack, adjust manual picks if needed, then run the sequence to compute and store the source static correction item. The Auto picking custom action automates picking across all sources. A sub-sequence can apply preprocessing to the data before picking.
Handle to the SEG-Y file providing random-access reading of source gathers. Required for building the minimum-offset stack line and for displaying individual source gathers in the interactive view.
Trace header table providing source coordinates and offset values used to select the minimum-offset trace for each source and to build the location map.
Replacement (near-surface) velocity (m/s) used to remove the expected offset moveout from the picked first-break time. Default: 1500 m/s. Set this to a value representative of the near-surface velocity in your survey area; typical values for land data are 1200–2000 m/s. Errors in V0 introduce a systematic bias proportional to the minimum offset divided by the velocity error.
The target zero-offset intercept time (s) to which all first-break picks are aligned. Default: 0.04 s. The static correction for each source is the difference between the alignment time and the estimated zero-offset first-break time at that source. Set this to the expected average first-break time at zero offset across the survey, or to the time of a reference datum reflector.
Container grouping the parameters that control interactive and automatic first-break picking behaviour.
Half-length (s) of the time window searched around a mouse-click location during manual picking. Default: 0.02 s. The snap magnet finds the nearest phase peak or energy maximum within this window. Increase if first breaks are not being snapped to correctly.
Polarity of the first-break arrival to pick. Options: Positive phase (default) or Negative phase. Choose to match the dominant polarity of the first-break wavelet in your data.
Minimum amplitude a sample must exceed (relative to the trace maximum) to qualify as a pick candidate. Default: 2.5. Increase to reject weak candidates on noisy first breaks; decrease if strong first breaks are being missed.
Controls how the manual pick snaps to the nearest event. Nearest (default) snaps to the sample closest in time to the click. Max energy snaps to the sample with the highest energy within the picking window. Use Max energy when first breaks arrive on a broad wavelet and exact onset time is less critical.
Width (s) of the time window searched during automatic first-break picking, centred on the expected first-break time derived from the alignment line. Default: 0.35 s. Widen for surveys with large lateral variation in first-break times; narrow to reduce false picks on data with reflections or multiples arriving early.
Algorithm used to find the first break during auto picking. Options: First break (default), Max energy, or Nearest. First break searches for the first sample in the window that exceeds the amplitude threshold. Max energy picks the sample with the highest absolute amplitude. Nearest picks the sample closest to the expected alignment time. First break is the most reliable choice for high signal-to-noise first arrivals. When First break is selected, the Start time for First break option parameter is activated.
Earliest time (s) from which the First break auto-picking algorithm begins its search. Default: 0.0 s. Active only when Auto picking type is set to First break. Set to a time just before the earliest expected first-break arrival to prevent the picker from latching onto noise or instrument transients at the start of the record.
Automatically picks the first-break arrival for every source in the dataset using the Auto picking type algorithm and Auto picking window settings. The resulting picks are displayed as the Picked time overlay on the minimum-offset stack. Review the picks on representative sources before running the full sequence to verify picking quality.
Removes all first-break picks for all sources in the current session. Use before restarting the auto-picking with different parameters, or to reset manual edits and start from scratch.