GUIDE TO THE PROGRAM PACKAGE SEIS version 11
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1. DESCRIPTION OF THE PACKAGE
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   THE PROGRAM PACKAGE IS DESIGNED FOR THE NUMERICAL MODELLING OF
SEISMIC WAVE FIELDS IN 2-D LATERALLY VARYING LAYERED STRUCTURES
BY THE RAY METHOD.
   THE PACKAGE CONSISTS OF SIX PROGRAMS: THE BASIC PROGRAM
CALLED  SEIS , AND FIVE AUXILIARY PROGRAMS,  SMOOTH ,  RAYPLOT ,
 SYNTPL ,  SEISPLOT  AND  POLARPLOT .

   THE BASIC PART OF ALL COMPUTATIONS IS PERFORMED IN THE PROGRAM
SEIS. IT CAN BE SUBDIVIDED INTO THREE PARTS: SEIS, MODEL AND RAY.
   IN THE PART 'SEIS', THE DATA CONCERNING THE COMPUTED WAVE FIELD
ARE READ IN. TWO-POINT RAY TRACING AND GENERATION OF ELEMENTARY
WAVES ARE CONTROLLED FROM THIS PART OF THE PROGRAM.
   IN THE PART 'MODEL', THE DATA CONCERNING THE MODEL OF MEDIUM
ARE READ IN AND CORRESPONDING APPROXIMATION OF INTERFACES AND
VELOCITY DISTRIBUTION IS PERFORMED. THIS PART OF THE PROGRAM SEIS
IS INTERCHANGEABLE. IN THE PRESENT VERSION, THE FOLLOWING TWO
'MODEL' PARTS OF SEIS ARE AVAILABLE (THEY DIFFER BY VELOCITY
APPROXIMATION WITHIN INDIVIDUAL LAYERS):
   I)   BICUBIC SPLINE INTERPOLATION
   II)  LINEAR INTERPOLATION BETWEEN ISOVELOCITY INTERFACES
IN ALL SPECIFIED CASES, INTERFACES ARE APPROXIMATED BY INTERPOLATING
CUBIC SPLINES.
   IN THE PART 'RAY', STANDARD RAY TRACING, DYNAMIC RAY TRACING
AND EVALUATION OF AMPLITUDES ARE PERFORMED. THIS PART AND ANY OF
'MODEL' PARTS CAN BE ALSO USED IN OTHER PROGRAMS BASED ON RAY
TRACING.

   THE PROGRAM  SEIS  MAY USE AS INPUT DATA THE DATA GENERATED IN
THE PROGRAM SMOOTH AND STORED IN THE FORMATTED FORM IN THE FILE LU,
(SEE BELOW). THE INPUT DATA CAN BE ALSO READ IN DIRECTLY. THE
PROGRAM SEIS GENERATES TWO FILES: FILE LU1 WITH DATA FOR PLOTTING
RAY DIAGRAMS, TRAVEL TIMES AND RAY AMPLITUDES AND FILE LU2 WITH
DATA FOR COMPUTATION OF RAY SYNTHETIC SEISMOGRAMS.
   PROGRAM SEIS CONSISTS OF THE FOLLOWING PARTS:
    SEIS.FOR ,  RAY.FOR ,  MODIS.FOR  (OR  MODSP.FOR ).
   THESE PARTS MUST BE LINKED TOGETHER BEFORE RUNNING THE
   PROGRAM. NONE OF THESE PARTS CAN WORK INDEPENDENTLY.

   THE PROGRAM  SMOOTH  MAY BE USED FOR THE PREPARATION OF
A SMOOTH VELOCITY INPUT DATA FOR THE PROGRAM SEIS IF BICUBIC
SPLINE INTERPOLATION IS USED IN SEIS TO APPROXIMATE THE
VELOCITY DISTRIBUTION, SEE I) ABOVE. THE PROGRAM PRODUCES
ONE FILE, FILE LU WITH THE VELOCITY INPUT DATA IN THE
FORMATTED FORM AS REQUIRED BY SEIS (SEE INPUT DATA CARD SUB 4,
BELOW).
   PROGRAM SMOOTH CONSISTS OF THE SINGLE PART:
            SMOOTH.FOR .

   THE PROGRAM  RAYPLOT  PERFORMS PLOTTING OF RESULTS STORED
IN THE FILE LU1, GENERATED BY SEIS. IT PRODUCES PLOTS
OF RAY DIAGRAMS, TIME-DISTANCE AND AMPLITUDE-DISTANCE CURVES.
   PROGRAM RAYPLOT CONSISTS OF THE FOLLOWING PARTS:
    RAYPL.FOR ,  SOURCE.FOR ,  BORDER.FOR ,
   AND REQUIRES   CALCOPS.FOR ,  CALCOPS.INC ,
    ERROR.FOR ,  LENGTH.FOR ,
    SEP.FOR  and  SEP.INC  OF PACKAGE FORMS.

    THE PROGRAM  SYNTPL  COMPUTES RAY SYNTHETIC SEISMOGRAMS FROM
THE DATA STORED IN FILE LU2, GENERATED IN SEIS. THE PROGRAM
GENERATES TWO FILES: FILE LU3, WHICH CONTAINS SAMPLED
SYNTHETIC SEISMOGRAMS (IN A NORMALIZED FORM), WHICH MIGHT BE
FURTHER PROCESSED AND PLOTTED IN PROGRAM SEISPLOT;
UNFORMATTED FILE LU4, WHICH CAN BE USED FOR PLOTTING
OF SEISMOGRAMS USING STANDARD SEISMIC ROUTINES SUCH AS ROUTINE
TRPLOT IN UNIX OPERATING SYSTEM IN SEP STANFORD.
    PROGRAM SYNTPL CONSISTS OF THE FOLLOWING PARTS:
             SYNTPL.FOR ,  SOURCE.FOR .

   THE PROGRAM  SEISPL  CAN BE USED TO PLOT THE SYNTHETIC
SEISMOGRAMS STORED IN FILE LU3, GENERATED BY THE PROGRAM
SYNTPL, IN A WAY COMMON IN SEISMOLOGY (EACH SEISMOGRAM IS
PLOTTED AS A SINGLE CURVE).
   PROGRAM SEISPLOT CONSISTS OF THE FOLLOWING PARTS:
    SEISPL.FOR ,  BORDER.FOR ,
   AND REQUIRES   CALCOPS.FOR ,  CALCOPS.INC ,
    ERROR.FOR ,  LENGTH.FOR ,
    SEP.FOR  and  SEP.INC  OF PACKAGE FORMS.

   THE PROGRAM  POLAR  CAN BE USED TO PLOT THE SYNTHETIC
PARTICLE MOTION DIAGRAMS FROM DATA STORED IN FILES LU3,
GENERATED BY THE PROGRAM SYNTPL.
   PROGRAM POLARPLOT CONSISTS OF THE FOLLOWING PARTS:
            POLAR.FOR ,  BORDER.FOR ,
   AND REQUIRES   CALCOPS.FOR ,  CALCOPS.INC ,
    ERROR.FOR ,  LENGTH.FOR ,
    SEP.FOR  and  SEP.INC  OF PACKAGE FORMS.



2. LIST OF FILES
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   SEIS PACKAGE CONTAINS 4 KINDS OF FILES: SOURCE PROGRAMS,
TEXT FILES DESCRIBING THE SOURCE PROGRAMS, INPUT DATA FOR TEST
EXAMPLE AND OUTPUT FILES FOR THE TEST EXAMPLES (UNFORMATTED
FILES ARE NOT INCLUDED). THE FILES ARE ORDERED IN THE FOLLOWING
WAY:

   I) FILES WITH SOURCE PROGRAMS (OR PARTS OF SOURCE PROGRAMS):
       SEIS.FOR ,  MODIS.FOR ,  MODSP.FOR ,  RAY.FOR ,  SMOOTH.FOR ,
       RAYPLOT.FOR ,  SYNTPL.FOR ,  SEISPL.FOR ,  POLAR.FOR ,  BORDER.FOR ,
       SOURCE.FOR .

   II) TEXT FILES:
        SEIS ,  SMOOTH ,  RAYPLOT ,  SYNTPL ,  SEISPLOT  AND  POLARPLOT .

   III) INPUT FILES FOR TEST EXAMPLE:
         SEIS.UNC ,  RAYPL.UNC ,  SYNTX.UNC ,  SYNTZ.UNC ,  SEISPL.UNC ,  POLAR.UNC .

   IV) OUTPUT FILES FOR TEST EXAMPLES:
        LU1.UNC ,  LU2.UNC ,  LU3X.UNC ,  LU3Z.UNC .

GOOD LUCK!

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