| C 1 CLIENT Atlantic Mar Geo COMPANY USGS CREW NO 0 |
| C 2 LINE 103 AREA SEAX-96004 MAP ID None |
| C 3 REEL NO 1 DAY-START OF REEL 139 YEAR 1996 OBSERVER |
| C 4 INSTRUMENT: MODEL SERIAL NO |
| C 5 DATA TRACES/RECORD 2 AUXILIARY TRACES/RECORD 0 CDP FOLD |
| C 6 SAMPLE INTERVAL 500 SAMPLES/TRACE 2048 BITS/IN EXB BYTES/SAMPLE
4 |
| C 7 RECORDING FORMAT SEGY FORMAT THIS REEL SEGY MEASUREMENT
SYSTEM |
| C 8 SAMPLE CODE: 1 (4 BYTE FLOATING) |
| C 9 GAIN TYPE: FIXED |
| C10 FILTERS: ALIAS NOTCH HZ BAND - HZ SLOPE - DB/OCT |
| C11 SOURCE: TYPE NUMBER/POINT POINT INTERVAL |
| C12 PATTERN: LENGTH WIDTH |
| C13 SWEEP: START HZ END HZ LENGHT MS CHANEL NO TYPE |
| C14 TAPER: START LENGHT MS END LENGHT MS TYPE |
| C15 SPREAD: OFFSET MAX DISTANCE GROUP INTERVAL |
| C16 GEOPHONES: PER GROUP SPACING FREQUENCY MFG MODEL |
| C17 PATTERN: LENGTH WIDTH |
| C18 TRACES SORTED BY: RECORD |
| C19 AMPLITUDE RECOVERY: |
| C20 MAP PROJECTION ZONE ID COORDINATE UNITS |
| C21 PROCESSING: |
| C22 ACOUSTIC SOURCE: H2O FIRE RATE: 5 SECS: |
| C23 |
| C24 |
| C25 |
| C26 |
| C27 |
| C28 |
| C29 |
| C30 |
| C31 |
| C32 |
| C33 |
| C34 |
| C35 |
| C36 |
| C37 |
| C38 |
| C39 |
| C40 END EBCDIC |
| Byte Numbers |
Header Value Description |
| 3201 - 3204 |
Job identification number. |
| 3205 - 3208 |
Line number. |
| 3209 - 3212 |
Reel number. |
| 3213 - 3214 |
Number of data traces
per record. |
| 3215 - 3216 |
Number of auxiliary traces per record. |
| 3217 - 3218 |
Sample interval, microseconds,
this file (reel). |
| 3219 - 3220 |
Sample interval, microseconds, original field
recording. |
| 3221 - 3222 |
Number of samples per
data trace, this file (reel). |
| 3223 - 3224 |
Number of samples per data trace, original field
recording. |
| 3225 - 3226 |
Data sample format code:
1 = floating point (4 bytes) 2 = fixed point (4 bytes) 3 = fixed point (2
bytes) 4 = fixed point with gain code (4 bytes). |
| 3227 - 3228 |
CDP fold. |
| 3229 - 3230 |
Trace sorting code: 1
= as recorded (no) sorting) 2 = CDP ensemble 3 = single fold continuous
profile 4 = horizontally stacked |
| 3231 - 3232 |
Vertical sum code: 1 = no sum 2 = two sum ...
N = N sum (N = 32,767) |
| 3233 - 3234 |
Sweep frequency at start. |
| 3235 - 3236 |
Sweep frequency at end. |
| 3237 - 3238 |
Sweep length, ms. |
| 3239 - 3240 |
Sweep type code: 1 = linear 2 = parabolic 3 =
exponential 4 = other |
| 3241 - 3242 |
Trace number of sweep channel. |
| 3243 - 3244 |
Sweep trace taper length, ms, at start if tapered. |
| 3245 - 3246 |
Sweep trace taper length, ms, at end. |
| 3247 - 3248 |
Taper type: 1 = linear 2 = cos 3 = other |
| 3249 - 3250 |
Correlated data traces: 1 = no 2 = yes |
| 3251 - 3252 |
Binary gain recovered: 1 = yes 2 = no |
| 3253 - 3254 |
Amplitude recovery method: 1 = none 2 = spherical
divergence 3 = AGC 4 = other |
| 3255 - 3256 |
Measurement system: 1
= meters 2 = feet |
| 3257 - 3258 |
Impulse signal: 1 = Upward = negative number.
2 = Upward = positive number. |
| 3259 - 3260 |
Vibratory polarity code - seismic signal lags
pilot signal by: 1 = 337.5 - 22.5 degrees 2 = 22.5 - 67.5 degrees 3 = 67.5
- 112.5 degrees 4 = 112.5 - 157.5 degrees 5 = 157.5 - 202.5 degrees 6 =
202.5 - 247.5 degrees |
|
Byte Numbers
|
Header Value Description
|
|
1
- 4
|
Trace
sequence number within line.
|
|
5
- 8
|
Trace
sequence number within file (reel)
|
|
9 - 12
|
Original
field record number
|
|
13 - 16
|
Trace number
within original field record
|
|
17 - 20
|
Energy source point number.
|
|
21 - 24
|
CDP ensemble number.
|
|
25 - 28
|
Trace number within the CDP
ensemble.
|
|
29 - 30
|
Trace identification
code: 1 = seismic data
|
|
31 - 32
|
Number of vertically summed
traces yielding this trace
|
|
33 - 34
|
Number of horizontally stacked
traces yielding this trace
|
|
35 - 36
|
Data use: 1 = production 2
= test
|
|
37 - 40
|
Distance from source point
to receiver group.
|
|
41 - 44
|
Receiver group elevation -
above sea level are positive, below sea level are negative.
|
|
45 - 48
|
Surface elevation at source.
|
|
49 - 52
|
Source depth below surface
(positive number).
|
|
53 - 56
|
Datum elevation at receiver
group.
|
|
57 - 60
|
Datum elevation at source.
|
|
61 - 64
|
Water depth at source (this
is the Fish depth below the sea surface in meters*10)
|
|
65 - 68
|
Water depth at group.
|
|
69 - 70
|
Scalar to be applied to all
elevations & depths, specified in bytes 41 - 68 to give the real value.
Scalar = 1, +/-10, +/-100, +/-1000, or +/-10,000. If positive, scalar
is used as a multiplier; if negative, scalar is used as a divisor.
|
|
71 - 72
|
Scalar to be applied to all
coordinate specified in bytes 73 - 88 to give the real value. Scalar =
1, +/-10, +/-100, +/-1000, or +/-10,000. If positive, scalar is used as
a multiplier; if negative, scalar is used as a divisor.
|
|
73 - 76
|
Source coordinate - X. UTM
Easting coordinate
|
|
77 - 80
|
Source coordinate - Y. UTM
Northing coordinate
|
|
81 - 84
|
Group coordinate - X. UTM
Easting coordinate
|
|
85 - 88
|
Group coordinate - Y. UTM
Northing coordinate
|
|
89 - 90
|
Coordinate units: 1 = length
(meters or feet) 2 = seconds of arc
|
|
91 - 92
|
weathering velocity.
|
|
93 - 94
|
Subweathering velocity.
|
|
95 - 96
|
Uphole time at source.
|
|
97 - 98
|
Uphole time at group.
|
|
99 - 100
|
Source static correction.
|
|
101 - 102
|
Group static correction.
|
|
103 - 104
|
Total static applied.
|
|
105 - 106
|
Lag time A. Time in ms between
end of 240-byte trace identification header and time break. positive if
time break occurs after end of header, negative if time break occurs before
end of header. Time break is defined as the initiation pulse which may
be recorded on an auxiliary trace or as otherwise specified by the recording
system.
|
|
107 - 108
|
Lag time B. Time in ms between
the time break and positive or negative.
|
|
109 - 110
|
Delay recording time. Time
in ms between initiation time of energy source and time when recording
of data samples begins.
|
|
111 - 112
|
Mute time - start.
|
|
113 - 114
|
Mute time - end.
|
|
115 - 116
|
Number
of samples in this trace.
|
|
117 - 118
|
Sample
interval, in microseconds, for this trace.
|
|
119 - 120
|
Gain type
of field instruments: 1 = fixed, 2 = binary, 3 = floating point, 4 = ---
N = optional use
|
|
121 - 122
|
Instrument gain constant.
|
|
123 - 124
|
Instrument
early or initial gain (db).
|
|
125 - 126
|
Correlated: 1 = no 2 = yes
|
|
127 - 128
|
Sweep frequency at start.
|
|
129 - 130
|
Sweep frequency at end.
|
|
131 - 132
|
Sweep length,
ms.
|
|
133 - 134
|
Sweep type: 1 = linear 2 =
parabolic 3 = exponential 4 = other
|
|
135 - 136
|
Sweep trace taper length at
start, ms.
|
|
137 - 138
|
Sweep trace taper length at
end, ms.
|
|
139 - 140
|
Taper type: 1 = linear 2 =
cos 3 = other
|
|
141 - 142
|
Alias filter
frequency.
|
|
143 - 144
|
Alias filter
slope.
|
|
145 - 146
|
Notch filter frequency.
|
|
147 - 148
|
Notch filter slope.
|
|
149 - 150
|
Low cut
frequency.
|
|
151 - 152
|
High cut
frequency.
|
|
153 - 154
|
Low cut
slope.
|
|
155 - 156
|
High cut
slope.
|
|
157 - 158
|
Year data
recorded (four digit integer).
|
|
159 - 160
|
Day of
year.
|
|
161 - 162
|
Hour of
day (24 hour clock).
|
|
163 - 164
|
Minute
of hour.
|
|
165 - 166
|
Second
of minute.
|
|
167 - 168
|
Time basis
code: 1 = local 2 = GMT 3 = other
|
|
169 - 170
|
Trace weighting factor - defined
as 2-N volts for the least significant bit. (N=0, 1,...,32,767)
|
|
171 - 172
|
Geophone group number of roll
switch position one.
|
|
173 - 174
|
Geophone group number of trace
number one within original field record.
|
|
175 - 176
|
Geophone group number of last
trace within original field record.
|
|
177 - 178
|
Gape size (total number of
groups dropped).
|
|
179 - 180
|
Overtravel associated with
taper at beginning or end of line: 1 = down (or behind) 2 = up (or ahead)
|
| 181 - 240 |
Unassigned - for optional information. |
U.S. Department of the Interior |
U.S. Geological Survey