Transect: Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE)

Processed By:
Part I: USGS Seismic Processing Center (Denver, Colorado)
Part II: Lithosphere and Canadian Shield Division (Ottawa)

Date Processed: 1987

Line B Migrated Section

Location: Lake Superior
Profile Length: 99.1 km
Shot Point: 111-2063

No. Processing History Line B

Part I
1 Format Conversion Yes

Demultiplexing
Yes

Record Length
20 s

Sample Interval
0.004 s
2 Recording Gain Removal Yes
3 Geometry Definition CMP
4 Editing Corrections Trace editing
5 Resampling 0.008 s
6 Filter F-K (in the shot domain)

Pass Band
4-45 Hz

Dip (per trace)
+/- 0.005 s

Width
13 traces

Length
31 samples
7 CDP Sort 24 or 30 fold
8 Amplitude Compensation AGC

Window
1 s
9 Velocity Analysis Yes
10 Preliminary Stack Yes
11 Multiple Suppression In the CDP domain

Correlation Velocity
1700 m/s

Application Gate
0-3 s
12 NMO Correction Yes
13 Mute First break noise suppression
14 Pre-Stack Deconvolution Spiking

Operator Length
59 samples

Windows
(0-4 s); (3-12 s); (10-20 s)
15 Stack 24 or 30 fold
16 Filter Bandpass (linear interpolation between application windows)

Time Variant
Yes

Time/Filter
(0-2 s: 4,8,30,36 Hz); (5-8 s: 4,8,28,31 Hz); (12-20 s:4,8,25,30 Hz)
17 Post-Stack Predictive Deconvolution 2nd zero crossing

Operator Length
53 samples

Windows
(0-5 s); (6-20 s)
18 Vertical Sum (4 to 1)

CMP Spacing
50 m
19 Amplitude Compensation AGC

Window
2.5 s
20 Post-Stack Amplitude Smoothing 2-D smoother

Smoothing
3 traces x 3 samples

Part II
21 Filter Yes

Bandpass Filter
Pre-migration (optional)

Pass Band
(7,9,35,30 Hz) or (14,17,35,40 Hz)

Velocity Filter
Pre-migration (optional)

Taper
+/- (3-3.9) km/s
22 Pre-Migration Tests F-K Constant Velocity

Velocity Interval
4000-8500 m/s

Velocity Increment
< or = 250 m/s
23 Migration F-K (linearly interpolated and smoothed velocity functions)

Time/Velocity
(0 s: 5750 m/s); (20 s: 6250 m/s)
24 Vertical Sum 2 to 1

Trace Spacing
100 m
25 Post-Migration Filter Yes

Coherency Filter
Compute

Dip Passband
+/- 3 km/s

Trace Aperture
9 trace

Coherency Filter
Apply

Formats Processed Comments
Structure Stack Yes (was also reprocessed in 1991)
DMO Stack No