****************************************
DESCRIPTION OF THE PROGRAM   S Y N T A N
****************************************


   PROGRAM SYNTAN IS DESIGNED FOR THE COMPUTATION OF RAY SYNTHETIC
SEISMOGRAMS FROM THE  DATA STORED IN THE FILE LU2 GENERATED IN
THE PROGRAM ANRAY. THE SEISMOGRAMS ARE CALCULATED IN THE TIME DOMAIN
USING APPROXIMATE EXPRESSIONS FOR THE HILBERT TRANSFORM OF THE GABOR
SIGNAL /2/. PROGRAM SYNTAN IS A MODIFICATION OF PROGRAM SYNTPL FROM 
PROGRAM PACKAGE SEIS83 /1/. THE FILE LU2 CONTAINS TRAVEL TIMES, RAY 
AMPLITUDES AND PHASE SHIFTS FOR ALL SPECIFIED RECEIVERS AND ALL 
ELEMENTARY WAVES. THE FILE ALSO CONTAINS SLOWNESS VECTORS SPECIFYING
CONSIDERED RAYS AT A SOURCE. PROGRAM SYNTAN GENERATES A NEW FILE LU4 
AND AN AUXILIARY (BINARY) FILE LU5 WITH SYNTHETIC SEISMOGRAMS. FOR 
PLOTTING SEISMOGRAMS, IT IS POSSIBLE TO USE THE PROGRAM SEISPLOT 
INCLUDED IN THIS PACKAGE.
    THE FOLLOWING THREE POINT SOURCES CAN BE CONSIDERED: A POINT FORCE,
A DOUBLE COUPLE SOURCE AND AN EXPLOSIVE (IMPLOSIVE) SOURCE. THE FORCE
SHOULD BE SPECIFIED IN NEWTONS, THE MOMENTS IN NEWTONMETERS. IF LENGTH
AND VELOCITY UNITS USED IN THE ANRAY PROGRAM ARE M AND M/S THEN THE
RESULTING DISPLACEMENTS DUE TO THE FORCE OR MOMENT SOURCE ARE IN 
10**(-3)M. IF THE LENGTH AND VELOCITY UNITS USED IN THE ANRAY PROGRAM
ARE KM AND KM/S, THE RESULTING DISPLACEMENTS ARE IN 10**(-12)M.
THE SOURCE-TIME FUNCTION USED IN SYNTAN IS A GABOR SIGNAL, I.E. A 
HARMONIC CARRIER MODULATED BY A GAUSSIAN ENVELOPE,
   F(T)=EXP(-(OMEGA*T/GAMA)**2)COS(OMEGA*T+PSI).          (1)
HERE T IS TIME, OMEGA=2.*PI*FREQ, AND FREQ, GAMA AND PSI ARE
THREE FREE PARAMETERS OF THE SOURCE-TIME FUNCTION. BY A PROPER
CHOICE OF THESE PARAMETERS, THE USER CAN SIMULATE A BROAD VARIETY
OF WAVELETS WHICH ARE CLOSE TO THOSE OBSERVED IN SEISMOLOGY AND
SEISMIC PROSPECTING (SEE DETAILS IN /2/).
  NOTE THAT THE ZERO TIME OF THE SIGNAL (1) CORRESPONDS TO THE
MAXIMUM OF ITS ENVELOPE, NOT TO ITS FIRST NON-ZERO VALUE. THIS GIVES
A TIME SHIFT OF THIS SIGNAL IN SYNTHETIC SEISMOGRAMS IN COMPARISON 
WITH OTHER SIMILAR SIGNALS (MUELLER SIGNAL,ETC.). THE USER,
WHO IS NOT SATISFIED WITH THIS SHIFT, CAN USE THE PARAMETERS
MSHIFT AND SHIFT READ FROM INPUT DATA TO REMOVE IT.
  WHEN COMPUTING THE SYNTHETIC SEISMOGRAMS FROM THE DATA STORED
IN THE FILE LU2, IT IS POSSIBLE TO SELECT ONLY CERTAIN DATA
FROM LU2.
 FIRST SELECTION IS PERFORMED USING THE INTERNAL WAVE CODE OF
ELEMENTARY WAVES, WHICH CORRESPONDS TO THE SUCCESSIVE NUMBER OF
THE ELEMENTARY WAVE AS IT IS GENERATED IN THE PROGRAM ANRAY, 
SEE DESCRIPTION OF ANRAY FOR DETAILS.
  THE SECOND SELECTION APPLIES TO EPICENTRAL DISTANCES. IT IS
POSSIBLE TO CONSTRUCT THE SYNTHETIC SEISMOGRAMS ONLY FOR SELECTED
RECEIVERS, AND NOT FOR THE WHOLE SYSTEM OF RECEIVERS FOR WHICH 
THE DATA IN ANRAY WERE COMPUTED.

POSITIVE POLARITY OF IMPULSES IS TO THE LEFT.

                                                     
DESCRIPTION OF INPUT AND OUTPUT FILES
-------------------------------------
    MAIN INPUT DATA ARE READ FROM THE STANDARD INPUT BY LIST-DIRECTED
INPUT (FREE FORMAT) AND CONSIST OF A SINGLE LINE CONTAINING FOLLOWING
DATA:
    'LIN' 'LOU' 'LU2' 'LU4' 'LU5'/
HERE:
    'LIN' IS THE NAME OF THE INPUT DATA FILE LIN.
    'LOU' IS THE NAME OF THE OUTPUT LOG FILE LOU.
    'LU2' IS THE NAME OF THE INTPUT DATA FILE LU2,
          GENERATED BY PROGRAM ANRAY.
    'LU4' IS THE NAME OF THE OUTPUT DATA FILE LU4.
    'LU5' IS THE NAME OF THE AUXILIARY DATA FILE LU5.
    / IS A SLASH RECOMENDED IN BATCH AND SCRIPT FILES TO ENABLE FUTURE
        EXTENSIONS.
DEFAULTS:
    'LIN'='syntan.dat'
    'LOU'='syntan.out'
    'LU2'='lu2.dat'
    'LU4'='lu4.dat'
    'LU5'='lu5.dat'
EXAMPLE OF THE MAIN INPUT DATA:
    'syntan.chs' /

INPUT DATA CONSIST PARTIALLY OF THE DATA OBTAINED IN THE PROGRAM
ANRAY, WHICH ARE STORED IN THE FILE LU2, AND PARTIALLY OF THE 
ADDITIONAL DATA READ BY LIST-DIRECTED INPUT (FREE FORMAT) AND
SPECIFIED BY THE USER IN THE FILE LIN. OUTPUT DATA DESCRIBING THE 
COMPUTATIONS ARE STORED IN THE FILE LOU. OUTPUT DATA FOR PLOTTING 
SYNTHETIC SEISMOGRAMS IN THE PROGRAM SEISPLOT ARE STORED IN THE 
FILES LU4.

                                                      
THE DATA STORED AT LU2
----------------------

THE DATA ARE STORED IN LU2 IN A FORMATTED FORM. FOR DETAILS SEE
THE DESCRIPTION OF THE CONTENT OF THE FILE LU2 IN PROGRAM ANRAY.

1) MTEXT                                       FORMAT(A)
2) NDST,KSH,ILOC                               FORMAT(26I3)
3) XSOUR,YSOUR,ZSOUR,TSOUR,RSTEP,ROS           FORMAT(8F10.5)
4) IF(NDST.NE.1) DST(I),I=1,NDST               FORMAT(8F10.5)
   IF(NDST.EQ.1) XREC,YREC,XPRF,XATAN          FORMAT(8F10.5)
5) NCODE,II,T,CAX,CAY,CAZ,TAST  FORMAT(2I3,F12.7,6E12.6,F10.6)
6) IF(NC.LT.0) CAX1,CAY1,CAZ1                  FORMAT(6E12.6)
7) (P(K),K=1,3)                                FORMAT(3F10.5)
8) (POL(K),K=1,3)                              FORMAT(3F10.5)
9) IF(NC.LT.0) (POL1(K),K=1,3)                 FORMAT(3F10.5)


THE DATA IN 5-9 CAN BE REPEATED ON LU2 MANY TIMES. IN THE PROGRAM
SYNTAN, THIS NUMBER MAY NOT EXCEED 2000. OTHERWISE IT WOULD BE
NECESSARY TO CHANGE THE DIMENSIONS IN THE PROGRAM. THE MAXIMUM 
NUMBER OF THE RECEIVER POSITIONS IS 100.


                                                      
THE ADDITIONAL INPUT DATA IN THE FILE LIN
-----------------------------------------

THESE DATA ARE SPECIFIED BY THE USER. THE DATA CONTROL THE 
COMPUTATION OF SYNTHETIC SEISMOGRAMS. IN THE DESCRIPTION OF 
ADDITIONAL INPUT DATA, THE PLACES WHERE THE DATA FROM LU2 ARE 
READ IN ARE DENOTED BY **LU2/1, **LU2/2, ETC.

1) ONE LINE
  MPRINT
     MPRINT... THE PARAMETER WHICH CONTROLS THE PRINTOUT ON THE
              LINE PRINTER, SEE DETAILS IN THE SECTION "OUTPUT
              TABLES".

**LU2/1
**LU2/2
**LU2/3
**LU2/4

2) ONE LINE, VARIOUS SWITCHES.
   MCOMP,MRED,MSELEC,MEPIC,MSHIFT,KABS,MSOUR
      MCOMP...  CONTROLS THE CHOICE OF THE COMPONENT OF THE
                DISPLACEMENT VECTOR.
                MCOMP=0: VERTICAL COMPONENT.
                MCOMP=1: COMPONENT ALONG THE X-AXIS.
                MCOMP=2: COMPONENT ALONG THE Y-AXIS.
      MRED...   CONTROLS REDUCTION OF TRAVEL TIMES. IF VSP
                SYNTHETICS ARE COMPUTED, MRED SET AUTOMATICALLY
                ZERO, MRED=0.
                MRED=0: TRAVEL TIMES NOT REDUCED.
                MRED=1: TRAVEL TIMES REDUCED. THE REDUCTION
                VELOCITY IS GIVEN IN THE LINE NO.3.
      MSELEC... CONTROLS SELECTION OF ELEMENTARY WAVES.
                MSELEC=0: ALL WAVES STORED AT LU2 ARE USED TO
                CONSTRUCT SYNTHETIC SEISMOGRAMS.
                MSELEC=1: ONLY SELECTED WAVES ARE USED TO CONSTRUCT 
                SYNTHETIC SEISMOGRAMS, SEE LINE NO.5.
      MEPIC...  CONTROLS SELECTION OF RECEIVERS.
                MEPIC=0: THE SYNTHETIC SEISMOGRAMS ARE CONSTRUCTED 
                AT ALL RECEIVER POSITIONS.
                MEPIC=1: THE SYNTHETIC SEISMOGRAMS ARE CONSTRUCTED 
                ONLY AT SELECTED RECEIVER POSITIONS, SEE
                LINE NO.4.
      MSHIFT... CONTROLS THE TIME SHIFT OF THE SIGNAL.
                MSHIFT=0: NO TIME SHIFT. ZERO TIME CORRESPONDS
                TO THE MAXIMUM OF THE ENVELOPE OF THE SIGNAL (1).
                MSHIFT=1: THE TIME SHIFT IS INTRODUCED 
                AUTOMATICALLY. IT CORRESPONDS TO THE TIME 
                INTERVAL BETWEEN THE MAXIMUM OF THE ENVELOPE 
                AND THE TIME, WHERE THE ENVELOPE IS 0.1 FROM 
                ITS MAXIMUM VALUE.
                MSHIFT=2: THE TIME SHIFT IS INTRODUCED MANUALLY,
                BY THE PARAMETER 'SHIFT' IN LINE NO.3.
      KABS...   SPECIFIES THE DISSIPATION TYPE. 
                ** IN THIS VERSION, IT HAS ONLY FORMAL MEANING. 
                NO ABSORPTION IS CONSIDERED. AUTOMATICALLY 
                KABS=0. **
                KABS=0: PERFECTLY ELASTIC MEDIUM.
                KABS=1: SLIGHTLY ABSORBING MEDIUM WITH NON-CAUSAL
                ABSORPTION.
                KABS=2: SLIGHTLY ABSORBING MEDIUM WITH CAUSAL
                ABSORPTION (FUTTERMAN'S MODEL).
      MSOUR...  CONTROLS THE TYPE OF THE CONSIDERED POINT SOURCE.
                MTYPE=1: SINGLE FORCE.
                MTYPE=2: DOUBLE COUPLE.
                MTYPE=3: EXPLOSIVE (IMPLOSIVE SOURCE).
 
3) ONE LINE, SPECIFICATION OF SYNTHETIC SEISMOGRAMS.
    TMIN,DT,TMAX,FREQ,GAMA,PSI,VRED,SHIFT,AROT
       TMIN,DT,TMAX... MINIMUM TIME, TIME STEP AND MAXIMUM
                TIME OF COMPUTED SYNTHETIC SEISMOGRAMS. IN CASE
                OF MRED=1, THESE QUANTITIES CORRESPOND TO THE
                REDUCED TRAVEL TIME.
       FREQ,GAMA,PSI...  PARAMETERS WHICH SPECIFY THE SOURCE-TIME
                FUNCTION (1).
                WHEN FREQ NOT SPECIFIED, FREQ=4.
                WHEN GAMA NOT SPECIFIED, GAMA=4.
       VRED...  REDUCTION VELOCITY.
                WHEN VRED NOT SPECIFIED, VRED=8.
       SHIFT... WHEN MSHIFT=2, SHIFT GIVES THE TIME SHIFT OF THE
                SIGNAL (1). OTHERWISE IT MAY BE ARBITRARY.
       AROT...  AN ANGLE, IN  RADIANS,  BY  WHICH  THE   HORIZONTAL 
                COORDINATE AXES OF THE RECORDING  COORDINATE SYSTEM  
                ARE TO BE ROTATED.
                FOR  AROT=0,  THE   RECORDING   COORDINATE   SYSTEM 
                COINCIDES WITH THE "MODEL" COORDINATE SYSTEM.   FOR   
                AROT.NE.0, THE  AXES OF  THE  RECORDING  SYSTEM ARE 
                ROTATED  ANTICLOCKWISE  IN THE  HORIZONTAL PLANE BY 
                THE ANGLE AROT.

4) ONE LINE, SELECTION OF RECEIVER POSITIONS.
  INCLUDED ONLY WHEN MEPIC.NE.0.
    NEPIC,(IEP(I),I=1,NEPIC)
        NEPIC...NUMBER OF SELECTED RECEIVER POSITIONS AT WHICH
                THE SYNTHETIC SEISMOGRAMS SHOULD BE CONSTRUCTED.
        IEP(1),IEP(2),...,IEP(NEPIC)... SEQUENTIAL NUMBERS OF
                SELECTED RECEIVER POSITIONS. THE RECEIVER 
                POSITIONS ARE NUMBERED BY THEIR INDICES IN THE 
                FIELD DST, SEE DATA STORED IN LU2, LINE 4.

5) ONE LINE, SELECTION OF WAVES
  INCLUDED ONLY WHEN MSELEC.NE.0.
    NSELEC,(ISEL(I),I=1,NSELEC)
        NSELEC...NUMBER OF SELECTED WAVES USED FOR THE 
                CONSTRUCTION OF SYNTHETIC SEISMOGRAMS.
        ISEL(1),ISEL(2),...,ISEL(NSELEC)... INTERNAL CODES OF
                SELECTED WAVES. THEY CORRESPOND TO THE SEQUENTIAL
                NUMBERS OF WAVES AS THEY WERE GENERATED IN ANRAY.

6) ONE LINE, REFERENCE FREQUENCY. 
  ** NOT CONSIDERED IN THIS VERSION. **
  INCLUDED ONLY IF KABS.NE.0.
    FREF,QRED
        FREF... REFERENCE FREQUENCY FOR ABSORPTION COMPUTATIONS.
                THE  VELOCITY VALUES AND QUALITY FACTOR USED IN
                THE MODEL ARE SPECIFIED FOR THE FREQUENCY FREF.
                DEFAULT VALUE, FREF=1.
        QRED... FACTOR BY WHICH GLOBAL ABSORPTION FACTORS "TAST"
                ALONG ALL RAYS ARE MULTIPLIED. IT CORRESPONDS TO
                DIVISION OF THE CORRESPONDING Q-FACTOR BY QRED.
                DEFAULT VALUE, QRED=1.

7) ONE LINE, SPECIFICATION OF PARAMETERS OF THE SOURCE.
  INCLUDED ONLY IF MSOUR.NE.0.
    IPAR(1),...,IPAR(4),PAR(1),...,PAR(6)

    MSOUR=1: SINGLE FORCE.

        IPAR(1)-IPAR(4)... FREE PARAMETERS.
        PAR(1)... FORCE AZIMUTH - THE ANGLE, IN RADIANS, MADE BY
                THE PROJECTION OF THE FORCE VECTOR INTO A 
                HORIZONTAL PLANE, AND THE POSITIVE X-AXIS. POSITIVE
                CLOCKWISE.
        PAR(2)... MAGNITUDE OF THE FORCE (IN N, I.E. KG*M/S**2).

        PAR(3)... FORCE DECLINATION - THE ANGLE, IN RADIANS, MADE
                BY THE FORCE VECTOR AND A HORIZONTAL PLANE.
        PAR(4)-PAR(6)... FREE PARAMETERS.

    MSOUR=2: DOUBLE COUPLE.

        IPAR(1)-IPAR(4)... FREE PARAMETERS.
        PAR(1)... DIP ANGLE - THE ANGLE, IN RADIANS, BETWEEN THE FAULT 
                AND A HORIZONTAL PLANE, IN RADIANS.
        PAR(2)... SOURCE MOMENT (IN NM, I.E. KG*M**2/S**2).
        PAR(3)... STRIKE ANGLE - THE ANGLE, IN RADIANS, BETWEEN POSITIVE
                X-AXIS AND THE INTERSECTION OF THE FAULT WITH A
                HORIZONTAL PLANE.
        PAR(4)... RAKE ANGLE - THE ANGLE, IN RADIANS, BETWEEN THE DIRECTION
                OF THE DISPLACEMENT ON THE FAULT AND THE INTERSECTION OF
                THE FAULT WITH A HORIZONTAL PLANE. POSITIVE ANTICLOCKWISE.
        PAR(5)-PAR(6)... FREE PARAMETERS.
        NOTE: THE FORMULAE FOR THE DOUBLE COUPLE FOLLOW THE 
        DEFINITION IN AKI AND RICHARDS /3/.

    MSOUR=3: EXPLOSIVE (IMPLOSIVE) SOURCE.

        IPAR(1)=1 (-1)... FOR EXPLOSIVE (IMPLOSIVE) SOURCE.
        IPAR(2)-IPAR(4)... FREE PARAMETERS.
        PAR(1)... MAGNITUDE OF THE SOURCE (IN NM, I.E. KG*M**2/S**2).          
        PAR(2)-PAR(6)... FREE PARAMETERS.

**LU2/5
**LU2/6
**LU2/7
**LU2/8
**LU2/9

Example of data LIN for anisotropic model (isosurface approximation)



TERMINATION OF THE COMPUTATIONS
-------------------------------

COMPUTATIONS TERMINATE AFTER THE SPECIFIED SEISMOGRAMS ARE CALCULATED.


                                                      
OUTPUT TO THE FILE LOU 
----------------------

ALL THE ADDITIONAL INPUT DATA ARE REPRODUCED ON THE LINE PRINTER.
ADDITIONAL PRINTOUT IS CONTROLLED BY THE PARAMETER MPRINT, SEE LINE 
NO.1 IN ADDITIONAL INPUT DATA.

FOR MPRINT=0, THE DATA LU2/1, LU2/2, LU2/3 AND LU2/4 ARE 
REPRODUCED. FOR EACH RECEIVER POSITION THE FOLLOWING QUANTITIES 
ARE ALSO PRINTED (IN ONE LINE): THE COORDINATE OF THE RECEIVER 
(X-COORDINATE IN CASE OF RECEIVERS SITUATED ON THE EARTH'S SURFACE
OR AN INTERFACE, Z-COORDINATE IN CASE OF RECEIVERS SITUATED ON
A VERTICAL PROFILE), THE MAXIMUM AMPLITUDE SMAX OF THE SEISMOGRAM, 
TIME TM CORRESPONDING TO THE FIRST NON-ZERO POINT OF THE SEISMOGRAM 
AND THE NUMBER NPS OF POINTS IN THE SEISMOGRAM. AT THE END OF 
COMPUTATIONS OF ALL SEISMOGRAMS, THE QUANTITY SMAXIM (THE MAXIMUM 
AMPLITUDE IN THE WHOLE SYSTEM OF SYNTHETIC SEISMOGRAMS) IS PRINTED.

FOR MPRINT=1, ALSO MODIFIED DATA LU2/5 ARE PRINTED. INSTEAD OF
COMPLEX AMPLITUDE COMPONENTS IN LU2/5, AMPLITUDE AND PHASE SHIFT
OF SPECIFIED COMPONENT ARE PRINTED.    

FOR MPRINT=2, NORMALIZED SEISMOGRAMS ARE ALSO PRINTED.

                                                      
OUTPUT TO THE FILE LU4
----------------------

THE FILE LU4 CONTAINS THE COMPUTED RAY SYNTHETIC SEISMOGRAMS
AT INDIVIDUAL RECEIVER POSITIONS TOGETHER WITH SOME OTHER IMPORTANT 
INFORMATION. THE ZERO SAMPLES IN THE INITIAL AND FINAL PARTS OF EACH 
SEISMOGRAM ARE NOT STORED. THE DATA ARE STORED IN THE FORMATTED 
FORM TO ALLOW FOR AN INSPECTION OF COMPUTATIONS. TO PERFORM THE 
PLOTTING OF SYNTHETIC SEISMOGRAMS FROM THE FILE LU4, THE PROGRAM 
SEISPLOT, INCLUDED IN THIS PACKAGE, CAN BE USED. THE DATA ON LU4 
ARE STORED IN THE FOLLOWING ORDER:

1) MTEXT                                       FORMAT(17A4)
  ARBITRARY ALPHANUMERIC TEXT DESCRIBING THE COMPUTATIONS. THIS
  TEXT WILL APPEAR UNDER THE PLOTS. THE TEXT WAS SPECIFIED IN
  THE PROGRAM ANRAY.
2) MMD,MRED,MCOMP,ITPR,VRED,RSTEP,XSOUR,YSOUR,DT  FORMAT(4I5,5F10.5)
     MMD...    THE NUMBER OF SELECTED RECEIVER POSITIONS.
     MRED...   MRED=0: NON REDUCED TRAVEL TIMES,
               MRED=0: REDUCED TRAVEL TIMES.
     MCOMP...  MCOMP=0: VERTICAL COMPONENT,
               MCOMP=1: COMPONENT ALONG THE X-AXIS,
               MCOMP=2: COMPONENT ALONG THE Y-AXIS.
     ITPR...   ITPR=0: RECEIVERS ALONG THE EARTH'S SURFACE,
               ITPR=1: RECEIVERS ALONG A VERTICAL PROFILE,
               ITPR.GT.100: RECEIVERS ALONG THE (ITPR-100)TH 
                            INTERFACE.
     VRED...   REDUCTION VELOCITY.
     RSTEP...  AVERAGE DIFFERENCE BETWEEN COORDINATES OF
               NEIGHBOURING RECEIVER POSITIONS.
     XSOUR, YSOUR... X- AND Y-COORDINATES OF THE SOURCE.
     DT...     TIME STEP IN SYNTHETIC SEISMOGRAM.
3) XMX,SMAXIM                             FORMAT(22X,F10.5,E15.9)
     XMX...    COORDINATE OF THE RECEIVER AT WHICH MAXIMUM
               AMPLITUDE SMAXIM WAS RECORDED.
     SMAXIM... THE MAXIMUM AMPLITUDE FROM ALL STORED SYNTHETIC
               SEISMOGRAMS.
THE FOLLOWING LINES 4,5 ARE SUCCESSIVELY REPEATED FOR ALL RECEIVER 
POSITIONS. THEY CONTAIN INFORMATION ABOUT INDIVIDUAL SEISMOGRAMS.
ONLY PARTS OF SEISMOGRAMS ARE STORED, STARTING WITH THE FIRST 
NON-ZERO SAMPLE AND ENDING WITH THE LAST NON-ZERO SAMPLE:
4) XX,SMAX,TM,NPS                    FORMAT(F10.5,E15.9,F10.5,I5)
     XX...     COORDINATE OF THE RECEIVER ON THE PROFILE
               (RADIUS FROM THE VERTICAL LINE THROUGH THE SOURCE
               FOR RECEIVERS ALONG A SURFACE OR AN INTERFACE
               PROFILE, 'MODEL' Z COORDINATE FOR RECEIVERS ALONG
               A VERTICAL PROFILE)
     SMAX...   MAXIMUM AMPLITUDE IN THE SYNTHETIC SEISMOGRAM
     TM...     TM IS THE TIME CORRESPONDING TO THE FIRST NON-ZERO 
               SAMPLE IN THE SEISMOGRAM. IF MRED.NE.0, TM
               IS A REDUCED TIME.
     NPS...    NUMBER OF POINTS IN SYNTHETIC SEISMOGRAMS.
5) SYNTHETIC SEISMOGRAMS IN NORMALIZED FORM:
   JS(I), I=1,NPS                              FORMAT(20I4)
     JS(I)..   I-TH SAMPLE, JS(I)=IFIX(999.1*SEIS(I)/SMAX),
               WHERE SEIS(I) IS COMPUTED VALUE OF I-TH NON-ZERO
               SAMPLE.

NOTE: THE MAXIMUM LENGTH OF THE SYNTHETIC SEISMOGRAMS IS 3001
POINTS.


                                                      
OUTPUT TO THE FILE LU5
----------------------

THE FILE LU5 IS AN AUXILIARY FILE. DATA STORED IN IT ARE STORED
IN AN UNFORMATTED FORM. THE FILE CAN BE USED FOR PLOTTING ON
SPECIAL SEISMIC PLOTTERS USING STANDARD ROUTINES. IN CONTRAST TO 
LU4, COMPLETE AND NON-NORMALIZED TRACES (ALL EQUALLY LONG) ARE 
STORED IN LU5. THE STRUCTURE OF THE FILE IS AS FOLLOWS:

1) NPTS,TMIN,DT,NDST,DIST(1),RSTEP
     NPTS,TMIN,DT... NUMBER OF POINTS, MINIMUM TIME AND TIME STEP
               IN SYNTHETIC SEISMOGRAMS (EQUAL FOR ALL TRACES).
     NDST,DIST(1),RSTEP... NUMBER OF TRACES, COORDINATE OF THE
               FIRST TRACE AND DISTANCE BETWEEN NEIGHBOURING 
               TRACES.
2) SAMPLED, NON-NORMALIZED TRACES ONE AFTER OTHER, ORDERED LIKE
   RECEIVERS.



REFERENCES
----------

/1/ CERVENY,V., PSENCIK,I.,1984, DOCUMENTATION OF EARTHQUAKE 
ALGORITHMS. SEIS83 - NUMERICAL MODELING OF SEISMIC WAVE FIELDS IN 
2-D LATERALLY VARYING LAYERED STRUCTURES BY THE RAY METHOD. 
E.R.ENGDAHL EDIT., REPORT SE-35, BOULDER,36-40.

/2/ CERVENY,V., MOLOTKOV,I.A., PSENCIK,I.,1977. RAY METHOD IN 
SEISMOLOGY. UNIVERZITA KARLOVA, PRAHA.

/3/ AKI,K., RICHARDS,P.,1980. QUANTITATIVE SEISMOLOGY. W.H.FREEMAN,
SAN FRANCISCO.