Description

This module computes the instantaneous envelope of each trace in a gather, using the Hilbert transform to derive the amplitude envelope of the seismic signal. It is used to highlight the overall energy content of reflections independent of waveform polarity and phase, which is useful for amplitude anomaly analysis, bright-spot detection, and general attribute-based interpretation. Optionally the module can output the time derivative or second time derivative of the envelope instead of the envelope itself, which sharpens the onset of energy changes and can help emphasize thin-bed tuning effects or subtle amplitude variations.

Input data

Seismic gather

The input seismic gather whose traces will be converted to their amplitude envelope (or a derivative of it). Any gather type and domain accepted by the flow can be used; no special preconditioning is required.

Parameters

Envelop type

Selects which quantity is written to the output trace. "Envelop" outputs the instantaneous amplitude envelope itself, computed as the magnitude of the analytic signal (the trace combined with its Hilbert transform). "Envelop derivative" outputs the time derivative of the envelope, which emphasizes where the envelope amplitude is changing fastest (rising or falling energy fronts). "Envelop derivative^2" outputs the second time derivative, which further sharpens these transitions and can highlight thin, closely spaced changes in reflectivity. Use the plain envelope for general amplitude/attribute analysis, and switch to a derivative option when you want to emphasize rapid changes in reflection strength, such as at bed boundaries or amplitude anomalies.

Default: Envelop. Change this only if you specifically need a derivative-based sharpening of the envelope rather than the envelope amplitude itself.

Output data

Seismic gather

A gather with the same geometry as the input, where each trace has been replaced by its amplitude envelope, envelope derivative, or envelope second derivative, according to the selected Envelop type.

References

Taner, M. T., Koehler, F. and Sheriff, R. E., 1979, Complex seismic trace analysis: Geophysics, 44, 1041-1063.