PURPOSE
OPENING THE PROGRAM
RUNNING THE PROGRAM
You will need to enter the correct name of the data file for our fieldwork ("mmff2.dat"). The matrix "a" contains gain settings for channels 1-12. You should alter these to roughly balance the amplitudes of all the traces.
Next enter your refraction layer model parameters (h0 and h1 (m) and v0 and v1 (m/ms)). These are used by the program to calculate the harmonic mean velocity.
"starttrace" and "stoptrace" are the channel numbers of the traces you wish to stack.
"rl" is the record length (ms). For our data use rl equals 250 ms. "gs" is the interval between shot points or between geophones (m).
OUTPUT
The middle panel shows the dynamically corrected traces and the bottom panel displays the stacked trace.
The second figure displays the harmonic mean velocity versus sample number (in other words time to 125 ms.
REPORT
Also include the reflection data and results and a discussion of the corrected traces and the final stack. What is the bedrock depth?
This MATLAB program or "script" can be used to apply the dynamic correction ("NMO") to common-mid-point seismic reflection data and to stack the adjusted traces.
The program can be found on some combination of: class floppy, class web site, P-drive class folder, class folder on Tischler PC’s or on the desktop of some of these PC’s. This is not a compiled program so you should work with a copy with a new name. In that way the original will remain correct.
Most of the changes you will make are highlighted on the program listing.
The top panel of the first figure displays the field data after gain adjustment. The vertical scale is amplitude and the horizontal scale is sample number where 512 sample intervals equals 125 ms (in other words only the first half of each trace is plotted).
The report should include your refraction travel time curves with calculated layer parameters.