Cull values that exceed the reading specified in the adjacent box. Culling works as follows: GeoSyn first works down the log to determine the average velocity, and then working down the log again, sums the time. While drawing the log as blocks, where the actual time minus the calculated time over a given depth range using the average velocity exceeds the culling value, the current log block is ended and a new block is started. This option faithfully reproduces the velocity field, but more coarsely, which can be useful for AVO analysis when you want to simplify the geologic model by removing tuning effects.

Select whether to apply a mean, median, or RMS constant average to the log portion between the shallowest and deepest top within your selection.

Select the log to block.

Do one of the following:

• Type start and stop depths and click Update.
• Click either Top or Bottom to select an absolute depth from the log or click All to select both.
  
• Click Get range from tops to select a range using the formation top names that also appear in the tops list selected in the Top Properties dialog box.