WAVES

WAVES computes elastic Rayleigh waves. Start with GENDIS 9.2.5, then run DISPER 9.2.6. Run GENWAV 9.2.7 to define a simulation geometry and parameters. IMPORTANT: Make sure the frequency increments are consistent between disper and waves (see 9.2.7.1). The waves.d file will then be input to WAVES. Outputs from WAVES include: The following are some plots generated from these outputs.

Figure 52: WAVES: Wavelet on left, group velocity dispersion on right. No significance to curve colors except that in the dispersion plot, the fundamental is Blue and higher modes are in Red. Soil representation is layer over half-space as shown in 9.2.5.1 and Figure 50 above.
\includegraphics[scale=.8]{Figurewaves1.pdf}

Figure 53: WAVES: Synthetic seismograms for Vertical (wavV.seg) and horizontal (wavR.seg) motion.
\includegraphics[scale=.8]{FigurewavesVR.pdf}

Figure 54: Hodogram for offset 5 meters. Requires bsegin.m, segyinfo.m, and hodo2plot.m in directory with wavV.seg and wavR.seg files (see 6.0.10).
\includegraphics[scale=.5]{FigurewavesH.pdf}

While Rayleigh waves are often described to have elliptical retrograde motion, that is not always the case. Depending on the source depth, receiver depth, and the geologic profile, the motion can be either prograde or retrograde. In Figure 54 we see that the motion is complex, starting out with an ellipse with a sub-horizontal major axis, evolving to a vertical major axis of elliptical motion. An alternative case that illustrates retrograde elliptical motion is computed for the same waves.d. The revised disper.d uses a homogeneous half-space model (two points to describe). The result is shown in Figure 55:

 show.tmp                                
       &disper                                                                 
       nlay=    2,                                                             
     rho= 0.1700E+04, 0.1700E+04,                                              
     mu= 0.6800E+08, 0.6800E+08,                                               
     lame= 0.9520E+09, 0.9520E+09,                                             
     zi= 0.0000E+00, 0.1000E+01,                                               
       deltz=    1.0000,                                                       
       modemx=1,                                                               
       nfreq=202, flo=  0.1000000E+01, delf= 0.48828122E+00,   jsmax=300, ksw=0
        pvlcty=0.0, pfreq=0.0, zend=100.0,                                     
       ofile='disper.tmp',                                                     
       octav1='phase.m', octav2='mat2.m',                                      
       curve='earth.crv', /                                                    
         1        0.000      200.00      800.00   1700.0
         2        1.000      200.00      800.00   1700.0

Figure 55: Hodogram at offset 5 meters for alternative half-space soil model, see show.tmp above. Sign conventions need to be taken into account when determining type of motion.
\includegraphics[scale=.5]{FigurewavesHS.pdf}