GUIDE TO THE PROGRAM PACKAGE SEIS88
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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, ALSO
CALLED  SEIS88  AND FOUR AUXILIARY PROGRAMS,  SMOOTH ,  RAYPLOT , 
 SYNTPL ,  SEISPLOT  AND  POLARPLOT .

   THE BASIC PART OF ALL COMPUTATIONS IS PERFORMED IN THE PROGRAM
SEIS88. 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 VE-
LOCITY DISTRIBUTION IS PERFORMED. THIS PART OF THE PROGRAM SEIS88
IS INTERCHANGEABLE. IN THE PRESENT VERSION, THE FOLLOWING TWO
'MODEL' PARTS OF SEIS88 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 INTER-
POLATING 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  SEIS88  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 FROM TERMINAL 
OR CARDS. THE PROGRAM SEIS88 GENERATES TWO FILES: FILE LU1
(UNFORMATTED) WITH DATA FOR PLOTTING RAY DIAGRAMS, TRAVEL TIMES
AND RAY AMPLITUDES AND FILE LU2 (FORMATTED OR UNFORMATTED) WITH
DATA FOR COMPUTATION OF RAY SYNTHETIC SEISMOGRAMS.
   PROGRAM SEIS88 CONSISTS OF THE FOLLOWING PARTS:
    SEIS.FOR ,  RAY.FOR ,  MODIS.FOR  (OR  MODSP.FOR ) AND  SERV.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 SEIS88 IF BICUBIC
SPLINE INTERPOLATION IS USED IN SEIS88 TO APPROXIMATE THE
VELOCITY DISTRIBUTION, SEE I) ABOVE. THE PROGRAM PRODUCES
ONE FILE, FILE LU WITH THE VELOCITY INPUT DATA IN THE FORMAT-
TED FORM AS REQUIRED BY SEIS88 (SEE INPUT DATA CARD SUB 4,
BELOW).
   PROGRAM SMOOTH CONSISTS OF THE FOLLOWING PARTS:
            SMOOTH.FOR  SMOOTH.FOR,  SERV.FOR .

   THE PROGRAM  RAYPLOT  PERFORMS PLOTTING OF RESULTS STORED
IN THE FILE LU1, GENERATED BY SEIS88. IT PRODUCES PLOTS
OF RAY DIAGRAMS, TIME-DISTANCE AND AMPLITUDE-DISTANCE CURVES.
CALCOMP PLOTTING ROUTINES ARE REQUIRED.
   PROGRAM RAYPLOT CONSISTS OF THE FOLLOWING PARTS:
    RAYPL.FOR ,  SOURCE.FOR ,  BORDER.FOR ,  SERV.FOR . 

   THE PROGRAM  SYNTPL  COMPUTES RAY SYNTHETIC SEISMOGRAMS FROM
THE DATA STORED IN FILE LU2, GENERATED IN SEIS88. THE PROGRAM 
GENERATES TWO FILES: FILE LU3, WHICH CONTAINS SAMPLED
SYNTHETIC SEISMOGRAMS (IN A FORMATTED AND NORMALIZED FORM),
WHICH MIGHT BE FURTHER PROCESSED AND PLOTTED IN PROGRAM SEIS-
PLOT; 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 ,  SERV.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). CALCOMP PLOTTING ROUTINES ARE
REQUIRED.
   PROGRAM SEISPLOT CONSISTS OF THE FOLLOWING PARTS:
            SEISPL.FOR ,  BORDER.FOR ,  SERV.FOR . 

   THE PROGRAM  POLAR  CAN BE USED TO PLOT THE SYNTHETIC
PARTICLE MOTION DIAGRAMS FROM DATA STORED IN FILES LU3, GENE-
RATED BY THE PROGRAM SYNTPL. CALCOMP PLOTTING ROUTINES ARE
REQUIRED.
   PROGRAM POLARPLOT CONSISTS OF THE FOLLOWING PARTS:
            POLAR.FOR ,  BORDER.FOR ,  SERV.FOR . 

NOTE: ALL THE PROGRAMS ARE WRITTEN IN FORTRAN IV. IN THE BEGIN-
NING OF EACH PROGRAM ROUTINE SERV IS CALLED WHICH ENABLES INTER-
ACTIVE OPENING OF REQUIRED INPUT AND OUTPUT FILE AND ALSO CON-
TROLS INITIALIZATION OF PLOTTING.

2. CONTENT OF THE DISC
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   THIS DISC 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 ,  SERV.FOR .

   II) TEXT FILES:
        SEIS88 ,  SMOOTH ,  RAYPLOT ,  SYNTPL ,  SEISPLOT  AND  POLARPLOT .

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

   IV) OUTPUT FILES FOR TEST EXAMPLES:
        LU1.UNC ,  LU2.UNC ,  LU3A.UNC ,  LU3B.UNC . 

GOOD LUCK!

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