ReWARD Project Refraction/Wide-Angle Reflections Database

INGV-Italy Unit of Milano

The following is the so called EGT format, which we used for our digital data processing.
It is a lightly modified version of the original, created at Geophysical Institute of Karlsruhe⁽¹⁾ for the first digitizations of analogical seimic signals coming from magnetic tape recordings carried out with the Mars-66⁽²⁾  seismic equipment. Then, the same procedure, in a better version, was adopted also at geophysical  Institute of the E.T.H.⁽³⁾, Zürich, and at our old Lab. at CNR-IGL, Milan⁽⁴⁾.
Most of our archived data are still in this format, but for a more convenient data exchange, in a near future they will be converted in the more common format SEG-Y [conversion table]  [ref.:  SEG webpages for techn. standard].

Header structure (example):

        columns :
        1---|----1----|----2----|----3----|----4----|----5----|----6----|----7----|----8
r  1 :  SC3   _1b _B033     EW I_GE  M88   78 1
o  2 :     112.450    76.404   125.000     65.37
w  3 :   12500   318     2     0    60     0     1
s  4 :    96  6 25 19 29 52.015+++ 96  6 25 19 30  1.006+++
   5 :  40 50.632 14 27.688   -125 40 49.804 14 23.173 -3267  220   20  -125
   6 :      -0.184     0.016     0.298     0.424     0.300     0.066    -0.316     0.342
   7 :      -0.134    -0.073     0.278     0.372     0.454     0.294     0.088     0.032
   8 :       0.115     0.195     0.431     1.032     .....     .....
  :::
  ::: 'N_sam' samples follow (in this case: 12500)
  :::

FORMAT :
   raw 1 :  A6,1x,I3,1x,A8,1x,A2,1x,A14,1x,I2
       2 :  4 F10.3
       3 :  7 I6
       4 :  2(5 I3,1x,F6.3,A3)
       5 :  2(I2,F6.3,1x),I6,1x,2(I2,F6.3,1x),4 I5
       6 :  13(I6)
       7 :   "  "
     :::::   "  "

 raw 1: Sismo_Id (6_3_8) : label of the seismogram [shot_profile_station]
              Comp (2)   : component of the seismometer [VR, NS (or RD), EW (or TR)]
        Instr_Id (4_4_4) : label of the instrumentation [city_type_number]
             Origin (1)  : origin of the digital wave-form
    ['0'=M88, '1'=M66(A/D:HP), '2'=M66(A/D:M88), '3'=unknown]

 raw 2:      Dist (10)   : distance shot-station [km]
             Azim (10)   : azimuth from shot to station [°] (clockwise, 0°=360°=North)
             Freq (10)   : mean sampling rate [samp/s]
             Dur (10)    : duration of the record [s]

 raw 3:     N_sam (6)    : N. of samples
            H_stat (6)   : station elevation [m]
  according to the 'Origin' value, the following 4 variables can be as in (A) OR (B) OR (C)
  (A) | Scale (6)   : value of the pre-amplifier input [uV/count]  |
      | Expo (6)    : exponent (base 2) of the data-word           |-- for Origin=0 or 2
      |   /     : no-meaning                                       |
      |   /     :  "    "                                          |
 (B) | A_gain (6) : gain-exponent (base 2) of the modulator on land   |
     | D_gain (6) :   "     "       "   "   "  "  A/D process         |-- for Origin=1
     | A_filt (6) : low-pass filter setting on land                   |
     | D_filt (6) :  "   "     "       "    during A/D step           |
  (C) |  / / / /    : all four variables with NO meaning           |-- for Origin = 3
  Pol (6)    : signal polarity sign [+1: correct; -1: to be inverted]

 raw 4:  Timing-information:
 Year(3) Mo(3) Day(3) Hour(3) Min(3) T0(6)    : first sample Date and Time (Rec-Time)
                               +++ R_flag(3)  : Rec-Time validation flag
                       ['1'=time valid; '0'=inferred-time]
 Years(3) Mos(3) Days(3) Hours(3) Mins(3) T0s(6) : Shot Date and Time (Shot-Time)
                                  +++ S_flag(3)  : Shot-Time validation flag
                       ['1'=time valid; '0'=supposed-time]

 raw 5:  Coordinates & charge information
     LaStDeg (2) : Station Latitude, degrees [°]
     LaStMin (7) :    "        "     minutes [']
     LoStDeg (2) :    "    Longitude, degrees [°]
     LoStMin (7) :    "        "     minutes [']
     H_shot (6)  : Shot elevation [+/-m; -m in the case of sea-shooting]
     LaShDeg (2) : Shot-Point Latitude, degrees [°]
     LaShMin (7) :   "    "      "      minutes [']
     LoShDeg (2) :   "    "   Longitude, degrees [°]
     LoShMin (7) :   "    "      "      minutes [']
     Batim  (5)  : Batimetry [-m; 0 if shooting on earth]
     Charge (5)  : total charge of seismic explosive [kg]
     N_charge(5) : N. of charges used for the shot
     Depth_ch(5) : Mean depth of the charges [+/-m; =H_shot in the case of sea-shooting]

 raw 6 and following:
     numerical data of the seismogram [units undefined, format: 8(F10.3)]
                                                                                                                                      or: 13(I6)

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