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This module is deprecated. It is provided for legacy workflows only.
The Time Variant Static Shift Filter detects and corrects time-variant static shifts between individual traces and a reference derived from the gather itself. The module analyses each trace using iterative cross-correlation within a sliding window, estimating the time-varying static shift at each position along the trace and then applying the inverse shift to produce a corrected output gather. Unlike conventional static corrections that apply a single bulk time shift per trace, this module resolves shifts that vary with time, making it suitable for datasets with non-stationary near-surface anomalies or cycle-skipping effects.
The module outputs three data streams: the corrected gather, a time-shift map showing the estimated shift as a function of trace and time, and a correlation coefficient map showing the quality of the fit at each position.
The standard input data connection carrying the SEG-Y handle, trace headers, and associated metadata. Connect this to the upstream module in the processing flow.
The seismic gather to be processed. This can be a shot gather, CMP gather, or any sorted gather. The module processes one gather at a time and corrects time-variant static shifts trace by trace.
The maximum allowable time-variant static shift in seconds that the filter will estimate and correct at any given time position. The cross-correlation search is restricted to lags within ±Max Time Shift at each window position. Set this to slightly larger than the maximum shift you expect in the data. Values that are too large increase the risk of cycle-skipping; values that are too small may leave residual shifts uncorrected.
Default: 0.04 s (40 ms).
The length of the sliding cross-correlation window in seconds. This window slides along each trace to estimate the local time shift at each position. A longer window produces a smoother, more stable shift estimate but reduces temporal resolution, potentially smearing shifts at boundaries between zones. A shorter window resolves rapid changes in shift but may be less stable on low signal-to-noise data.
Default: 0.5 s.
The number of iterations of the time-variant shift estimation and correction cycle. After each iteration, the previously corrected gather is used as input for the next iteration, progressively refining the shift estimate. Increasing iterations can recover larger shifts that would otherwise cause cycle-skipping in a single pass, at the cost of increased processing time. A value of 1 is sufficient for small residual shifts; use 2–4 iterations when large or complex time-variant shifts are present.
Default: 1.