Calculate a Pseudo-Relief Attribute (TECVA)
Generating a pseudo-relief attribute (also known as TECVA) can assist with structural interpretation. It is often easier to correlate events on the enhanced reflectors, simplifying both fault and horizon interpretation.
Reference: Bulhoes, E. M., 2005, Principio da SismoCamada Elemantar e sua aplicacao a Tecnica Volume de Amplitudes (tecVA). Ninth International Congress of the Brazilian Geophysical Society.
- Go to the Process tab, add a Volume Maths (Simple) process (see Volume Maths Process (Simple)).
Volume Maths (Simple) settings:
- Volume 1 and Volume 2: Select the input stack.
- Use the multiply operation: x volume.
- The result will be a selectable volume.
Next, average the squared input stack from the previous process.
- In the Process tab, add a new Volume Smoothing process (see Volume Smoothing).
- Volume: select the created volume from the previous process.
- A new volume will be created.
Next, find the square root of the average (from the previous process).
- Add a Volume Maths process from the process tab (see Volume Maths).
- Click the blue "+" in the Volume Maths panel.
Volume Maths settings:
- Symbol: v1 - select the volume created from the averaging steps.
- Formula: sqrt (v1)
- A new volume is created.
Phase rotate the pseudo-RMS using a process.
- Add a Phase Rotation process (see Phase Rotation)
Phase Rotation settings:
- Volume: select the square root volume.
- Degrees: -90
- The new volume is created.
Finally, apply a Low-cut filter to remove low-frequency vertical striping.
- In the Process tab, add a Band-pass Filter process (see Band-pass Filter process).
Band-pass Filter settings:
- Volume: choose the phase-rotation volume
- File type: choose High-pass
- Windowing Model: select <<Whole Trace>>
- Stop: 2Hz
- Pass: 3Hz
- If the result looks "smeared", try increasing both the Stop and Pass values by 1 or 2 Hz.