# 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. 1. Go to the Process tab, add a Volume Maths (Simple) process (see Volume Maths Process (Simple)).
2. Volume Maths (Simple) settings:
• Volume 1 and Volume 2: Select the input stack.
• Use the multiply operation: x volume.
3. The result will be a selectable volume. Next, average the squared input stack from the previous process.

1. In the Process tab, add a new Volume Smoothing process (see Volume Smoothing).
2. Volume: select the created volume from the previous process.
3. A new volume will be created. Next, find the square root of the average (from the previous process).

1. Add a Volume Maths process from the process tab (see Volume Maths).
2. Click the blue "+" in the Volume Maths panel.
3. Volume Maths settings:
• Symbol: v1 - select the volume created from the averaging steps.
• Formula: sqrt (v1)
4. A new volume is created. Phase rotate the pseudo-RMS using a process.

1. Add a Phase Rotation process (see Phase Rotation)
2. Phase Rotation settings:
• Volume: select the square root volume.
• Degrees: -90
3. The new volume is created. Finally, apply a Low-cut filter to remove low-frequency vertical striping.

1. In the Process tab, add a Band-pass Filter process (see Band-pass Filter process).
2. Band-pass Filter settings:
• Volume: choose the phase-rotation volume
• File type: choose High-pass
• Windowing Model: select <<Whole Trace>>
• Stop: 2Hz
• Pass: 3Hz
3. If the result looks "smeared", try increasing both the Stop and Pass values by 1 or 2 Hz.   