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This module is deprecated. It is provided for legacy workflows only.
The Surface Multiple Modelling (1 layer) module generates a synthetic shot gather dataset representing a single flat horizontal reflector with optional first-order surface multiples. The model is constructed analytically using hyperbolic travel-time equations for both primary reflections and surface-related multiples. Each generated shot gather contains the same set of traces; the module simply repeats the gather for each specified shot position and writes all results to an output SEG-Y file. This module is useful for testing multiple attenuation algorithms on controlled synthetic data before applying them to real datasets.
The module has no data stream inputs and requires no connection to other processing modules. All parameters define the geometry and physics of the synthetic model directly.
This module does not require input seismic data. It generates synthetic traces from scratch based on the specified acquisition geometry and reflector model.
The spatial interval between consecutive shot positions in the synthetic geometry, in metres. This value also defines the basic distance unit used to compute receiver offsets. Adjust this to match the nominal shot point interval of the real acquisition you are modelling.
Default: 25 m.
The total number of shot gathers to write to the output file. Each gather is identical in content (same primary and multiple travel times) but has headers filled with incrementing shot position coordinates. This controls the total size of the output dataset.
Default: 128.
The receiver spacing expressed as a multiple of the shot distance. The actual offset step in metres equals this value multiplied by the Distance between shots. For example, with a shot distance of 25 m and an offset increment of 4, receivers are spaced 100 m apart.
Default: 4.
The number of traces per shot gather, corresponding to the number of receivers in each shot. Traces are evenly spaced from zero offset to the maximum offset defined by this count times the offset step. Increase this value to simulate a longer spread or wider offset range.
Default: 30.
The two-way zero-offset travel time to the primary reflector, in milliseconds. This sets the depth of the reflector at zero offset from which the hyperbolic travel-time curve is computed for all offsets. Set this to the expected primary reflection time in the target window of the real data you are modelling.
Default: 1000 ms.
The propagation velocity of the single layer above the reflector, in m/s. This velocity is used to compute the NMO curve for primary reflections and to determine the travel time of the first-order surface multiple. Use a value representative of the water column or near-surface layer in your dataset.
Default: 2000 m/s.
The output trace sample interval in seconds. This controls the temporal resolution of the synthetic traces. Use 0.002 for 2 ms sampling or 0.004 for 4 ms sampling. The output trace length is computed automatically based on the geometry to include all arrivals.
Default: 0.004 s (4 ms).
A flag (0 or 1) that controls whether first-order surface-related multiples are included in the synthetic. Set to 1 to add the surface multiple arrival (which has twice the zero-offset time of the primary) alongside the primary reflection. Set to 0 to generate primaries only.
Default: 1 (multiples included).
The dominant (peak) frequency in Hz of the Ricker wavelet used as the source signature for both primary and multiple reflections. Lower frequencies produce a broader wavelet and smoother appearance; higher frequencies improve temporal resolution but require finer sampling. Match this to the dominant frequency of the real data being modelled.
Default: 15 Hz.
The full path and file name of the output SEG-Y file (.sgy or .segy) where the synthetic shot gathers will be written. Use the file browser to select the output location. The file will contain all shot gathers concatenated in order, with trace headers populated according to the defined geometry.