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This module is deprecated and is no longer recommended for new projects.
RMS Velocity from Interval converts a 3D interval velocity field to an RMS velocity field using the Dix formula. It reads an interval velocity gather (in depth or time), integrates the squared interval velocities with respect to two-way time over the specified output time grid, and writes the resulting RMS velocity gather. The output velocity model can then be used for NMO correction, multiple attenuation, or other time-domain processing steps that require an RMS velocity field. The module corrects for a floating datum by replacing the velocity in the near-surface zone above the datum with the specified replacement velocity.
The input interval velocity gather from which RMS velocities are computed. This is typically the output of a depth-domain velocity model (tomography, ray tracing, or FWI) stored as a gather with traces representing vertical velocity profiles at each CMP or bin location.
The reference datum elevation (in metres) for the conversion. The default value is -99999.9, which disables the datum correction. Set this to the seismic datum elevation (in the same vertical coordinate system as the velocity model) to apply a floating-datum correction; the zone between the surface and this datum will be filled with the Replacement Velocity.
The constant velocity (in m/s) used to fill the zone between the surface topography and the reference datum during the Dix conversion. The default is 1500 m/s. This value should match the replacement velocity used during static corrections for the survey. It is only applied when Datum is set to a valid elevation value.
The sample interval (in seconds) of the output RMS velocity gather. The default is 0.004 s (4 ms). This should match the sample rate of the seismic data to which the RMS velocity model will be applied. A finer sample rate increases the accuracy of the Dix integration but also increases the size of the output velocity gather.
The maximum two-way time (in seconds) up to which the RMS velocity model is computed. The default is 4 s. Set this to the record length of the seismic data to ensure the output velocity model covers the full time range needed for NMO or other processing. Values beyond this time are not included in the output.