Collection  P851 120195
| Filename | hr454_FIN_stack.sgy |
| Proposal | P851 |
| Date Type | Seismic SEGY |
| Object Type | Digital Data |
| Format | SEGY |
| File Size | 417060240 (bytes) |
| Upload Date | 2018-10-25 |
| Description | 2D multichannel seismic (MCS) data were collected aboard the R/V Atlantis in June/July 2018 as part of the NSF-funded site survey cruise AT40-03. We used two arrangements: (1) slow ship speed (5 knot), high resolution (72-channel) recording, and (2) high ship speed (8 knot), low resolution (16-channel) recording. This line was collected with the high-speed, high resolution configuration as follows. The acoustic source was a pair of 45/105 in3 Sercel GI (Generator-Injector) airguns each hung at 3 m water depth from a single floating hanger centered 26 m aft of the starboard quarter and fired on distance every 50 m (roughly every 12 s). The source-receiver offset was 134 m (center of the airgun bridle to center of the first streamer section). The streamer comprised two parts: the forward 300 m was a 48-channel Geometrics GeoEel Solid Digital streamer, 6.25 m between groups. The aft 300 m was a 24-channel Geometrics GeoEel Liquid-Filled Digital streamer, 12.5 m between groups. Digi-Course depth-controllers with 0.5 m guard lines above and below the 3-m target tow depth were attached forward of channel 1, at channels 33 and 57, and at the tail of channel 72. Data were written to disk at 1 msec sampling and 9.5 to 8 s record lengths (depending on depth to basement) in SEGD format, later converted to SEGY. Processing was as follows. Traces from channels 33 and 57 were removed due to towing noise caused by depth controllers at these locations. A correction of between 40 and 46 msecs was determined empirically to place each shot instant at 0.0 secs recording time. This corrected for the intentional 50 msec delay between the time-zero trigger and the gun fire command and small variations in gun-streamer geometry between separate seismic gear deployments. A Butterworth filter with corner frequencies of 10,20,250,500 Hz was applied to reduce noise. Due to the relatively short offsets and deep water target reflectors, a brute velocity structure resulted in stacked traces that were visually indistinguishable from those for which rms velocities derived from semblance displays of common midpoint gathers were used for normal moveout correction. |
| Data Owner | Gregory Mountain, Rutgers University |
| Access Control | hold |
| Reason For Hold | |
| Start Time | 2018-07-01 |
| End Time | 2018-07-01 |
| DOI | |
| Georeference Type | Line |
| Geolocation | westernmost longitude: -37.528 easternmost longitude: -37.528 northernmost latitude: 43.8508 southernmost latitude: 43.4962 |
| Sites | WNAT-04A
WNAT-41A |
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