Plotting the Results from Merge

Initial plots are produced by a call to bplt in Merge. This program can output a variety of formats, including the *.jpg image format in the current script. The *.jpg files can be viewed using a program like display which comes with the ImageMagick package on most Linux distributions. The Merge script uses the jpg option for a quick QC. The program bplt is new with this release of BSU, and has many more options, to be discussed later. The scripts, xplot and psplot give some additional examples.

Alternatively, one can also use Seismic Unix (SU) to plot the results. The BSU distribution includes some scripts, xPlot-su and psPlot-su, which call SU programs for plotting in an X-window or as a Postscript file. Figure 16 illustrates how plots made with psPlot can be combined in xfig with the results of a direct push survey by ConeTec. The ConeTec survey was done in preparation for the field day event.

Figure 16: Difference of Source Polarizations, T-Component (bequ applied to twav.seg)
\includegraphics[scale=.8]{Figure5}

The twave.seg file has been trace equalized by the program bequ. If each trace were not individually scaled, the large variation in amplitude would result in the deep data disappearing below the visible threshold. The SH-wave arrives just before the 0.1 second timing line at the bottom of the survey. A faint, unidentified wave arrives at about .05 seconds (between what may be the P- and SH-waves).

Figure 17 shows the pwav.seg file, also processed by bequ. In this case, the scaling was based on the data from 0 to .025 seconds. What may be the P-wave arrives at about .02 seconds at the bottom of the survey. The file named pwav.seg is in fact the sum of the two source polarizations, vertical component. This process will also enhance Rayleigh and Near Field waves, so one should be cautious in identifying candidate P-waves. The shallower the depth, the more uncertain the wave field identification due to a superposition of different motions.

The plotting script which generated these figures, psPlot, makes use of the Seismic Unix program, segyclean, to prepare the headers before piping it to supswigp which does the actual plotting.

Figure 17: Sum of Source Polarizations, V-Component (bequ applied to pwav.seg)
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