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The basic shell script is
#!/bin/sh ##### # create a model ##### cat > SCM.mod << EOF MODEL.01 Simple crustal model ISOTROPIC KGS FLAT EARTH 1-D CONSTANT VELOCITY LINE08 LINE09 LINE10 LINE11 H(KM) VP(KM/S) VS(KM/S) RHO(GM/CC) QP QS ETAP ETAS FREFP FREFS 10.0000 6.0000 3.5500 2.8000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 6.0000 3.5500 2.8000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 6.0000 3.5500 2.8000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 6.0000 3.5500 2.8000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 8.0000 4.7000 3.3000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 8.0000 4.7000 3.3000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 8.0000 4.7000 3.3000 0.00 0.00 0.00 0.00 1.00 1.00 10.0000 8.0000 4.7000 3.3000 0.00 0.00 0.00 0.00 1.00 1.00 EOF ##### # do surface waves ##### sprep96 -L -M SCM.mod -PER 20.0 sdisp96 slegn96 sdpegn96 -L -C -TXT slegn96 -DER sdpder96 -L -C -TXT
The -L flag indicates that we are looking Love wave propagation. The model is a single layer over a halfspace, but with layers finely divided. We want to look at the value of the eigenfunctions at the layer interfaces and also the partial derivatives in the layers. After running this script we have two files:
SLEGN.TXT
LOVE WAVE MODE # 0 N T F C U ARE GAMMA 1 20.00 0.5000E-01 3.8012 3.4220 0.53573E-03 0.00000E+00which gives the phase and group velocity for the model at a period of 20.0s econds. ARE = 1/2cUIo and GAMMA relates to anelastic attenuation.
SLDER.TXT
Model: LAYER H(km) Vp(km/s) Vs(km/s) Density QA(inv) QB(inv) 1 10.00000 6.00000 3.55000 2.80000 0.00000 0.00000 2 10.00000 6.00000 3.55000 2.80000 0.00000 0.00000 3 10.00000 6.00000 3.55000 2.80000 0.00000 0.00000 4 10.00000 6.00000 3.55000 2.80000 0.00000 0.00000 5 10.00000 8.00000 4.70000 3.30000 0.00000 0.00000 6 10.00000 8.00000 4.70000 3.30000 0.00000 0.00000 7 10.00000 8.00000 4.70000 3.30000 0.00000 0.00000 8 10.00000 8.00000 4.70000 3.30000 0.00000 0.00000 LOVE WAVE MODE # 0 T = 0.2000E+02 C = 0.3801E+01 U = 0.3422E+01 AL= 0.5357E-03 GAMMA= 0.0000E+00 ZREF= 0.0000E+00 M UT TT DC/DH DC/DB DC/DR 1 0.100E+01 0.000E+00 -0.105E-01 0.394E+00 -0.352E-01 2 0.950E+00 -0.347E+00 -0.105E-01 0.331E+00 -0.215E-01 3 0.806E+00 -0.660E+00 -0.105E-01 0.230E+00 0.412E-03 4 0.582E+00 -0.908E+00 -0.105E-01 0.130E+00 0.222E-01 5 0.301E+00 -0.106E+01 0.000E+00 0.491E-01 0.180E-01 6 0.185E+00 -0.655E+00 0.000E+00 0.186E-01 0.680E-02 7 0.114E+00 -0.403E+00 0.000E+00 0.703E-02 0.257E-02 8 0.699E-01 -0.248E+00 0.000E+00 0.428E-02 0.156E-02
This gives the UT and TT at the layer boundary and the partial derivatives of the phase velocity with respect to layer thickness, S velocity and density.
3.801 + [0.331] * [ 0.1 ] = 3.834 km/sChange the model, get the new phase velocity and verify that the partial derivatives are correct.