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Interpret a seismic line

In this exercise we are going to interpret the seabed and basement of the seismic line. First we need to display the seismic line we want to interpret.

1. Right click the seismic line and select Seismic display.
2. Right click the seismic line and select Zoom to Data

Next we open the Seismic Interpretation (Xi) dialog:

• Locate Seismic Interpretation under Tools in the main menu.

First we need to select where our interpretations should be stored:

1. Click Browse button to select the interpretation folder
2. Select the seismic interpretation folder 3.Sediment Data / Seismic Interpretations

Next we need to specify the horizons we want to interpret:

1. Click the button in order to create a new IHorizon. The IHorizon dialog will appear
2. Type in Seafloor as the name of the new horizon, and click OK
3. Click the Graphical Settings tab
4. Set Line Width to 5
5. Check the User Defined Color and pick a color for the horizon.
6. Click OK
7. Click the same new button again, and call the next horizon Sediment Base.

Interpreting with auto-tracking:

1. To select Snap mode look at the seismic display and identify the reflector representing the seabed. Compare the color of the seabed reflector with the seismic color table. The color on the left side of the color table represents minima; the color on the right represents maxima. The seismic color table used is one of three:

   1. current active seismic color table – look in the lower right corner of Geocap.
   2. the color table specified in Seismic display, if any.
   3. the color table dragged and dropped on top of the seismic line, if any.
2. Select Snap mode accordingly.
3. Select Track mode to be Auto.
4. Set Delta Z. Delta Z is the maximum allowable vertical distance between two auto-tracked points. Z is usually time in ms. A good rule of thumb is that Delta Z should be the double of the sample interval in the seismic. In our case that is 8.
5. Pick the horizon to autotrack by clicking pressing the <space> or p key on the keyboard
6. The horizon is automatically interpreted
7. If the interpretation stopped at one point press <space> or p again to continue where it stopped.
8. When you are happy with the interpretation click the Image Added button