Introduction
The purpose of this problem is to make some wholespace synthetic
seismograms
1. Read the manual that is located on crust.eas.slu.edu at
/home/rbh/PROGRAMS.330/DOC/OVERVIEW.pdf/cps330.pdf, e.g.,
acroread
/home/rbh/PROGRAMS.330/DOC/OVERVIEW.pdf/cps330.pdf
2. Using the program mkmod96 to create the following
velocity model (NOTE give this the name 2half.mod):
H Vp Vs
Density Qp Qs Etap Etas FrefP FrefS
-4 1 0 1.0 0 0 0 0 1 1
2 2 0 1.5 0 0 0 0 1 1
3. Plot the model using shwmod96
4. Create a distance file, which you will name dfile, with
entries "Distance DT NPTS T0 VRED" for the distances used for
figure 3.2.2 in the text, e.g., you will require entries such as
1.2 0.05 256 0.0 0.0
1.6 0.05 256 0.0 0.0
......
6.8 0.05 256 0.0 0.0
5. Use the program hprep96 to create the data file for hspec96:
hprep96 -M 2half.mod -HS -1.0 -HR -1.5 -ALL -TH -BH -d dfile -TH -BH
then run the program hspec96
hspec96
and convolve with the source time
function
hpulse96 -V
-p -l 4 > file96
and them plot the figure using fprof96
fprof96 -S
2.0 < file96
You can view the plot with the following
commands:
plotxvig <
FPROF96.PLT
or you can get a PostScript file that you can
plot using the command
plotnps -F7 -W10 -K < FPROF96.PLT > my.ps
Of course you can also look at the traces using gsac by
creating the SAC waveform files using the command
f96tosac -B < file96
Question: What are the differences in
the synthetics between using hwhole96 and hspec96?
7. Repeat using the hprep96
command forcing a layer with a free surface over a
halfspace
hprep96 -M 2half.mod -HS -1.0 -HR -1.5 -ALL -TH -BH -d dfile -TF
hspec96
hpulse96
-V -p -l 4 > file96
plotxvig
< FPROF96.PLT
7. Repeat using the hprep96 command forcing
a layer with a rigid surface over a halfspace
hprep96 -M 2half.mod -HS -1.0 -HR -1.5 -ALL -TH -BH -d dfile -TR
hspec96
hpulse96
-V -p -l 4 > file96
plotxvig
< FPROF96.PLT
8. Discuss
the differences in the synthetics, especially in the polarities of the
reflected arrivals for the rigid and free surfaces