Table T1. Acquisition and processing parameters.
Parameter Survey 1203 Survey 1204 Survey F-2-87-AA Survey 1205 Survey 1206
Acquisition parameters:

Sample interval (ms):

 1 1 4 1 1

Record length (s):

 5 5 10 3 3

Source:

 80-in3 water gun 80-in3 water gun 80-in3 water gun 80-in3 water gun 80-in3 water gun

Source depth (m):

 6 6 Unknown 5 5

Receiver depth (m):

 15 15 Unknown 15 15

Source-receiver offset (m):

 450 218 400 218 218

Source interval (s; constant):

 6 6 10 4 4

Source spacing (m; depends on ship speed):

 15–20 15–20 40–50 10–15 10–15
Processing flow:

Source signature deconvolution:




Operator length (ms):

 150 — — — —

Signature length (ms):

4999 — — — —

Time shift for output (ms):

 0 — — — —

White-noise level (%):

 0.1 — — — —

Channel stack

 No No Yes No No

Static shift (ms):

 –100 –100 –100 –100 –100

NMO correction (m/s):

 1500 1500 1500 1500 1500

Minimum phase deconvolution:




Operator length (ms):

 90 — — — —

Prediction distance (ms):

 3 — — — —

Design window (ms above seafloor reflection):

 ~1200 — — — —

White-noise level (%):

 0.1 — — — —

Minimum phase deconvolution:




Operator length (ms):

 90 220 160 — —

Prediction distance (ms):

 3 3 8 — —

Design window (ms below seafloor reflection):

 ~1000 ~1200 ~1500 — —

White-noise level (%):

 0.1 0.1 0.1 — —

Spiking deconvolution:




Operator length (ms):

 — — — 300 3

Design window (ms above seafloor reflection):

 — — — ~800 ~300

White-noise level (%):

 — — — 0.1 0.1

Butterworth bandpass filter:




Phase:

 Zero Zero Zero Zero Zero

Pass-band (Hz):

 40–80 40–120 40–120 65–170 60–170

Low roll-off (dB/octave):

 18 18 18 18 18

High roll-off (dB/octave):

 72 36 72 36 36

True amplitude recovery:




Basis:

 Spherical spreading (1/t·v2) Spherical spreading (1/t·v2) Spherical spreading (1/t·v2) Spherical spreading (1/t·v2) Spherical spreading (1/t·v2)

Velocity model:

 Constant at 1500 m/s Constant at 1500 m/s Constant at 1500 m/s Constant at 1500 m/s Constant at 1500 m/s

Water column mute

 Yes Yes Yes Yes Yes

Trace kill

 Yes Yes Yes Yes Yes

F-K migration:




Stolt stretch factor:

 0.6 0.6 0.6 0.6 0.6

Velocity model:

 Constant at 1500 m/s Constant at 1500 m/s Constant at 1500 m/s Constant at 1500 m/s Constant at 1500 m/s

Notes: For Survey 1203, the first break of source signature occurs at t = 40 ms. — = no value.