Stacking velocities.

The stacking velocities are collected along the seismic lines and processed to show time versus velocity of the seismic reflectors. The data is used to generate a time velocity cube.

Before using then uncritical it is common to display and check the quality and extent to see how deep the cube should go.

The stacking velocities are located as in 06_Velocities as Survey03 and Survey04. There are more surveys in the dataset Tutorial data1 , but in this project we only need 3 and 4.

Exercise

Display stacking velocity.

Do Zoom to Folder on Survey03.
Open up folder Survey03; click on a stacking velocity dataset.
Perform Map Data. Zoom in and study the display. The lines are mapped.
Erase and perform Make bands of velocity an map. Zoom in and study the display. It is solid.
Try different display commands on the various velocity data sets.
Go to the Command panel. Use Display survey lines. Transfer this command to the Toolbar.
Highlight folder Survey03 and apply Display survey lines from the Toolbar.

Survey lines and stacking velocities

Stacking velocities collected and mapped

Gridding stacking velocities requires that all lines are collected into one file.

Exercise

Appending stacking velocity into one file.

Highlight folder Survey03 and apply Append all lines in a folder from the Command section under Schema Commands.
The result is appendedData in workspace. Create an temporary folder and put it there. Rename it to appendedData1.
Perform Append all lines in a folder on Survey04.
Put appendedData into the temporary folder.
Perform Append all lines in a folder on the temporary folder. The final result is now appendedData in workspace.
Transfer appendedData in workspace to the project under 06_Velocities and rename it all_lines.
Delete the temporary folder.

Note on appending data

We did not use Append all lines in a folder on the 06_Velocity folder because there are data in it that should not be appended.
Appending could have been done quicker with the shell command mhi/mlo data app. The menu uses these commands.
We could have avoided the temporary folder if we appended once; then edited the Append all lines in a folder on the next survey and clicked on Prestep and removed the command dhi appendedData which means delete workspace data appendedData. Then we can continue to append without deleting in the prestep. The final result is appendedData which we can transfer to the project.

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