SEG Y/Full header table

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SEG YSEG Y/Full header table
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Start byte Bytes Description Note
1 4 Trace sequence number within line Strongly recommended
5 4 Trace sequence number within file
9 4 Original field record number Strongly recommended
13 4 Trace number in original field record Strongly recommended
17 4 Energy source point number
21 4 Ensemble number, e.g. CDP, CMP, etc.
25 4 Trace number within ensemble
29 2 Trace identification code, see below Strongly recommended
31 2 Vertically summed traces in this trace
33 2 Horizontally summed traces in this trace
35 2 Data use: 1 for Prod, 2 for Test
37 2 Distance from source point to receiver group
41 4 Receiver elevation above datum
45 4 Source elevation above datum
49 4 Source depth below surface
53 4 Datum elevation at receiver
57 4 Datum elevation at source
61 4 Water depth at source
65 4 Water depth at receiver
69 2 Multiplier for all depths and elevations (negative for divisor)
71 2 Multiplier for all coordinates (negative for divisor)
73 4 Source X coordinate
77 4 Source Y coordinate
81 4 Receiver X coordinate
85 4 Receiver Y coordinate
89 2 Coordinate units: 1 length, 2 seconds, 3, decimal degree, 4 DMS
91 2 Weathering layer velocity
93 2 Sub-weathering layer velocity
95 2 Uphole time at source in ms
97 2 Uphole time at receiver in ms
99 2 Static correction at source in ms
101 2 Static correction at receiver in ms
103 2 Total static applied in ms
105 2 Time in ms between end of trace header and time break
107 2 Time in ms between the time break and source initiation time
109 2 Time in ms between source initiation and data recording
111 2 Mute start time in ms
113 2 Mute end time in ms
115 2 Samples in trace Strongly recommended
117 2 Sample interval, ms Strongly recommended
119 2 Gain type of field instruments: 1 fixed, 2 binary, 3 fp, 4+ optional
121 2 Instrument gain constant, dB
123 2 Instrument early or initial gain, dB
125 2 Correlated: 1 no, 2 yes
127 2 Sweep frequency at start, Hz
129 2 Sweep frequency at end, Hz
131 2 Sweep length, ms
133 2 Sweep type: 1 linear, 2 parabolic, 3 exponential, 4 other
135 2 Sweep taper length at start, ms
137 2 Sweep taper length at end, ms
139 2 Taper type: 1 linear, 2 cos, 3 other
141 2 Alias filter frequency, Hz
143 2 Alias filter slope, dB/octave
145 2 Notch filter frequency, Hz
147 2 Notch filter slope, dB/octave
149 2 Low-cut frequency, Hz
151 2 High-cut frequency, Hz
153 2 Low-cut slope, dB/octave
155 2 High-cut slope, dB/octave
157 2 Year
159 2 Day of year
161 2 Hour
163 2 Minute
165 2 Second
167 2 Time basis code: 1 local, 2 GMT, 3 other, 4 UTC
169 2 Trace weighting factor
171 2 Geophone group number of roll switch position 1
173 2 Geophone group number of first trace in original field record
175 2 Geophone group number of last trace in original field record
177 2 Gap size
179 2 Over travel associated with taper: 1 down, 2 up
181 4 X coordinate of ensemble position of this trace Recommended
185 4 Y coordinate of ensemble position of this trace Recommended
189 4 3D inline number Recommended for 3D
193 4 3D crossline number, usually same as ensemble number in bytes 21–24 Recommended for 3D
197 4 Shotpoint number, probably 2D only Recommended for 2D
201 2 Shotpoint number scalar, to apply to bytes 197–200
203 2 Trace value measurement unit
205 4 Transduction constant mantissa
209 2 Transduction constant exponent
211 2 Transduction units
213 2 Device identifier
215 2 Time value scalar, to give time in ms
217 2 Source type and orientation
219 6 Source energy direction
225 6 Source measurement
231 2 Source measurement unit
233 Unassigned, for optional information