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<< Click to Display Table of Contents >> Navigation: Velocity > Mute by angle range |
Mute by angle range applies an angle-domain mute to pre-stack seismic gathers. For each trace and time sample, the module computes the incidence angle using the Vrms velocity model (or optionally an interval velocity model) and then zeroes traces that fall either inside or outside a specified angle range. This allows selective retention or removal of near-angle, mid-angle, or far-angle portions of a gather, which is essential for AVO analysis, noise suppression at high reflection angles, and conditioning data before pre-stack inversion.
The angle boundaries can be specified as a single pair of constant values (Simple mode) or as a time-varying table (Table mode). The module also outputs the computed angle-versus-time curves and the taper mask for QC in the Graphics panel.
The standard seismic data container carrying the pre-stack CIG gathers to be muted.
SEG-Y file handle for reading trace data from disk.
Trace header vector providing offset and geometry information required for angle calculation.
Pre-stack gather (CIG or offset gather) to which the angle mute will be applied.
Stack line geometry for 2D surveys.
Crooked line geometry for 2D surveys with non-straight acquisition.
3D bin grid defining inline/crossline coordinates.
Pre-sorted trace index used to iterate gathers in the correct order.
Root-mean-square velocity model used to convert offset and two-way time into a reflection angle. Connect the output of a velocity analysis or NMO module. This input drives the angle computation for all formulas except Straight ray.
Optional interval velocity model. When connected and the Vrms to angle formula is set to Dix-Snell, the Dix equation is applied to the interval velocity rather than the Vrms model, giving a more accurate angle estimate. Leave disconnected to use only the Vrms model.
Controls which part of the gather is zeroed. Default: Inside. Inside zeros traces whose incidence angle falls between From angle and To angle; Outside zeros traces outside that range (i.e., retains only the specified angle band). Use Inside to suppress a noisy angle zone; use Outside to extract a specific angle partial stack.
Near-surface reference velocity (m/s) used in the Snell's law component of the angle calculation. Default: 1800 m/s. Set this to the velocity of the shallowest layer at the source-receiver surface.
Selects how the angle range is defined. Default: Simple. Simple uses constant From angle and To angle values applied uniformly across all times; Table uses the Time-angle factors table to define time-varying angle boundaries.
Minimum angle of the mute window in degrees. Default: 0°. Active when Mute data type is Simple. For example, set to 0° and To angle to 30° to apply an outer mute retaining only the near- and mid-angle range.
Maximum angle of the mute window in degrees. Default: 45°. Active when Mute data type is Simple. Traces with incidence angles above this value (outside mode) or between From/To angle (inside mode) are zeroed.
When enabled (default), the angle boundary curves are interpolated spatially between picked control points before applying the mute. Disable for a step-function mute that changes discontinuously from one picked location to the next.
When enabled (default), amplitude values within the taper zone around the angle boundary are smoothly tapered rather than step-zeroed. Disable to produce a hard edge at the angle boundary without any cosine taper.
Formula used to convert the Vrms model and offset into a reflection angle. Default: Dix-Snell fast. Dix-Snell applies the full Dix inversion followed by Snell's law ray bending at each layer — most accurate but slowest. Dix-Snell fast uses a faster approximation suitable for most surveys. Radius derives angle from the CRE radius parameter. Straight ray uses a simple linear raypath assumption (sin θ = offset / (2 × Vrms × t)), which is fast but less accurate at large angles.
Table of time–angle pairs defining time-varying From angle and To angle boundaries. Active when Mute data type is Table. Add rows with the two-way time (s) and corresponding minimum and maximum angles at each control time; the module interpolates between rows.
Angular step (degrees) between constant-angle lines drawn on the gather display in the Graphics panel. Default: 5°. Reduce for finer angular grid lines on the display; increase for a less cluttered view.
When enabled, input data items are automatically connected from the nearest upstream module with matching output types.
Specifies what to do when NaN or Inf sample values are encountered. Fix replaces bad values with zero; Notify logs a warning and replaces them; Continue passes bad values through without modification.
When enabled, the module also computes and outputs the difference between the input and the muted gather (i.e., the removed energy). This output is available in the Gather of difference output slot and is useful for QC of what was removed.
Selects the processing device. CPU is standard; GPU may accelerate processing on large 3D surveys.
Configuration for distributed (cluster) execution.
Minimum number of gathers sent per work chunk during distributed execution.
When enabled, restricts CPU thread count per cluster node to the value in Number of threads.
Optional text appended to the distributed job name.
When enabled, applies the CPU affinity mask specified in Affinity.
CPU affinity mask applied when Set custom affinity is enabled.
Maximum number of CPU threads used during execution.
When enabled, this module is bypassed and data passes through unchanged.
The angle-muted seismic data container. Pass to downstream AVO analysis, pre-stack inversion, or stack modules.
SEG-Y file handle for writing the muted output to disk.
Trace headers corresponding to the muted output traces.
The angle-muted gather for display or further processing.
Stack line geometry passed through from input.
Crooked line geometry passed through from input.
Bin grid passed through from input.
Sorted trace index passed through from input.
The removed energy (input minus muted output). Available when Calculate difference is enabled. Use to QC the muted zones — ideally this gather should show only the energy that was intentionally removed and not coherent signal.