**************************************** 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. PROGRAM SYNTAN IS A MODIFICATION OF PROGRAM SYNTPL FROM PROGRAM PACKAGE SEIS83 /1/. THE FILE LU2 CONTAINS TRAVEL TIMES, AMPLITUDES AND PHASE SHIFTS FOR ALL SPECIFIED RECEIVERS AND ALL ELEMENTARY WAVES. THE FILE ALSO CONTAINS THE INITIAL ANGLES OF CORRESPONDING RAYS. PROGRAM SYNTAN GENERATES A NEW FILE LU3 AND AN AUXILIARY FILE LU4 WITH SYNTHETIC SEISMOGRAMS. THESE SYNTHETIC SEISMOGRAMS CAN BE PLOTTED BY STANDARD PLOTTING ROUTINES, AVAILABLE AT MANY INSTITUTIONS. FOR PLOTTING SEISMOGRAMS, IT IS ALSO 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 HARMONIC CARRIER MODULATED BY A GAUSSIAN ENVELOPE, F(T)=EXP(-(OMEGA*T/GAMA)**2)COS(OMEGA*T+PSI), (1) WHERE 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 ARRIVAL. 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. DESCRIPTION OF INPUT AND OUTPUT DATA ------------------------------------ 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 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 AND ON SPECIAL SEISMIC PLOTTERS ARE STORED IN THE FILES LU3 AND LU4 RESPECTIVELY. SPECIFICATION OF THE FILES LIN, LU2, LU3 AND LU4 CAN BE MADE THROUGH THE ROUTINE SERV, WHICH IS PART OF THIS PROGRAM PACKAGE. IF THE ROUTINE SERV IS NOT USED (PUT 'C' IN FRONT OF 'CALL SERV' IN THE BEGINNING OF MAIN PROGRAM), THE FILES LIN AND LOU ARE AUTOMATICALLY SPECIFIED LIN=5, LOU=6, AND THE NUMBERS LU2, LU3 AND LU4 ARE READ IN FROM THE FILE LIN, SEE BELOW. Positive polarity of impulses is to the left of vertical time axis 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(17A4) 2) NDST,KSH,ITPR FORMAT(26I3) 3) XSOUR,YSOUR,ZSOUR,TSOUR,RSTEP,ROS,VPS,VSS FORMAT(8F10.5) 4) DST(I),I=1,NDST FORMAT(8F10.5) 5) NCODE,II,T,CAX,CAY,CAZ,CAX1,CAY1,CAZ1,DEC,AZIM,TAST FORMAT(2I3,F10.5,12E12.6,3F10.6) THE DATA IN 5 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 DATA 1-5 CAN BE READ IN FROM DIFFERENT FILES (SEE ADDITIONAL DATA, LINE 8) GENERATED IN THE PROGRAM ANRAY FOR A GIVEN MODEL, SOURCE AND RECEIVER POSITIONS. NOTE THAT THIS POSSIBILITY CAN BE USED ONLY IN OPERATING SYSTEMS ALLOWING SPECIFICATION OF THE NUMBER OF A FILE OUTSIDE THE SOURCE PROGRAM (E.G.IBM OPERATING SYSTEM). NOTE THAT 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 LU2,LU3,MPRINT,LU4 FORMAT(26I3) LU2... NUMBER OF THE FILE IN WHICH THE IMPULSE SYNTHETIC SEISMOGRAMS COMPUTED IN THE PROGRAM ANRAY ARE STORED. IT HAS NO MEANING IF ROUTINE SERV IS USED. LU3... NUMBER OF THE FILE IN WHICH THE SYNTHETIC SEISMOGRAMS COMPUTED IN THIS PROGRAM ARE STORED. IT HAS NO MEANING IF ROUTINE SERV IS USED. MPRINT... THE PARAMETER WHICH CONTROLS THE PRINTOUT ON THE LINE PRINTER, SEE DETAILS IN THE SECTION "OUTPUT TABLES". LU4... NUMBER OF AN AUXILIARY FILE USED IN SYNTAN FOR STORAGE OF SYNTHETIC SEISMOGRAMS IN UNFORMATTED FORM FOR PLOTTING OF SEISMOGRAMS ON SPECIAL SEISMIC PLOTTERS. IF LU4 IS NOT SPECIFIED, THEN LU4=10. IT HAS NO MEANING IF ROUTINE SERV IS USED. **LU2/1 **LU2/2 **LU2/3 **LU2/4 2) ONE LINE, VARIOUS SWITCHES. MCOMP,MRED,MSELEC,MEPIC,MSHIFT,KABS,MSOUR FORMAT(26I3) MCOMP... CONTROLS THE CHOICE OF THE COMPONENT OF THE DISPLACEMENT VECTOR. MCOMP=0: VERTICAL COMPONENT. MCOMP=1: RADIAL COMPONENT. MCOMP=2: TRANSVERSE COMPONENT. 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 FORMAT(8F10.5) 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. 4) ONE LINE, SELECTION OF RECEIVER POSITIONS. INCLUDED ONLY WHEN MEPIC.NE.0. NEPIC,(IEP(I),I=1,NEPIC) FORMAT(26I3) 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) FORMAT(26I3) 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 FORMAT(8F10.5) 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) FORMAT(4I5,6F10.5) 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 TERMINATION OF THE COMPUTATIONS ------------------------------- COMPUTATIONS TERMINATE IF BLANK LINE IS INSERTED AFTER THE LINE 8 WITH LU=0. OUTPUT TO THE FILE LOU ---------------------- ALL THE ADDITIONAL INPUT DATA ARE REPRODUCED ON THE LINE PRINTER. THE OTHER 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 LU3 ---------------------- THE FILE LU3 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 LU3, THE PROGRAM SEISPLOT, INCLUDED IN THIS PACKAGE, CAN BE USED. THE DATA ON LU3 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,DT FORMAT(4I5,4F10.5) 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: RADIAL COMPONENT, MCOMP=2: TRANSVERSE COMPONENT. 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... DUMMY PARAMETER (XSOUR=0.). 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 LU4 ---------------------- THE FILE LU4 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 LU3, COMPLETE AND NON-NORMALIZED TRACES (ALL EQUALLY LONG) ARE STORED IN LU4. 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.