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Depth-migrated High Resolution seismic reflection profiles and interval velocity models in the western Black Sea
This seismic data set was recorded in September 2015 on board the R/V Pourquoi Pas? during the GHASS cruise (IFREMER) on the western Black Sea, offshore Romania. The available profiles (part of the collected data) within this deposit are located on the continental slope, bathymetry between 500 to 1200 meters.
The pre-processing of the seismic data included common midpoint binning @6.25 meters, trace and shot edition, source delay correction, and a 35-375 Hz band pass filtering. Detailed Root Mean Square Velocity analyses were performed on semblance panels computed using super gathers every 150 m. Normal Move Out time correction was then applied on the Common Mid Point (CMP) using these velocities prior to stack. Interval velocities were computed using the Dix equation. The velocity model was then interpolated every CMP location, converted to depth and smoothed to perform post-stack depth migration.
The depth migrated sections and the depth velocity models have been output to standard SEG-Y rev1 format (https://library.seg.org/pb-assets/technical-standards/seg_y_rev1-1686080991247.pdf) with values written using “big-endian” byte ordering and IEEE floating-point. For a given profile, both SEGY files have the same number of traces and the same bin locations. Velocity unit is in meter.second-1. The depth sampling is set to 0.5 meter for both files. The recording delay is zero for the depth migration SEGY files. The delay is coded in meters and constant for a given depth velocity SEGY file, stored within the Trace Header (bytes 109-110). Trace coordinates are also stored within the Trace Header using WGS84 +DDDMMSS.ss format with a scale factor of -100 (bytes 81-88, which means that the value has to divided by 100) . For more convenient access to the location of the profiles, these coordinates are also stored into ASCII files using decimal degrees.
Disciplines
Marine geology
Keywords
Seismic reflection, depth migration, velocity model
Location
44.1768N, 43.8057S, 31.2833E, 30.6379W
Devices
High Resolution seismic equipment (https://archimer.ifremer.fr/doc/00283/39469/)
These High Resolution seismic data were recorded using the SEAL428 equipment and a solid streamer form SERCEL. The streamer had 96 traces with a 6.25 m spacing. The seismic source carried mini-GI air guns, with a total volume ranging from 13 to 48 cubic inch depending on the water depth, supplied by 2000 psi air pressure. The depth of the source was set to 1.5 m and the depth of the streamer to 2 m in order to preserve the high frequency content of the signal: central frequency ranging from 110 to 150 Hz depending on the mini-GI configuration. The distance between source and traces ranges from 50 to 650 meters
Data
File | Size | Format | Processing | Access | |
---|---|---|---|---|---|
Depth-migrated seismic reflection profile GAS30d | 52 Mo | SEGY | Processed data | ||
Velocity model of profile GAS30d | 29 Mo | SEGY | Processed data | ||
Location of profile GAS30d traces | 110 Ko | ASC | Processed data | ||
Depth-migrated seismic reflection profile GAS31a | 56 Mo | SEGY | Processed data | ||
Velocity model of profile GAS31a | 30 Mo | SEGY | Processed data | ||
Location of profile GAS31a traces | 160 Ko | ASC | Processed data | ||
Depth-migrated seismic reflection profile GAS33c | 27 Mo | SEGY | Processed data | ||
Velocity model of profile GAS33c | 15 Mo | SEGY | Processed data | ||
Location of profile GAS33c traces | 76 Ko | ASC | Processed data | ||
Depth-migrated seismic reflection profile GAS34a | 28 Mo | SEGY | Processed data | ||
Velocity model of profile GAS34a | 15 Mo | SEGY | Processed data | ||
Location of profile GAS34a traces | 80 Ko | ASC | Processed data | ||
Depth-migrated seismic reflection profile GAS34b | 44 Mo | SEGY | Processed data | ||
Velocity model of profile GAS34b | 17 Mo | SEGY | Processed data | ||
Location of profile GAS34b traces | 126 Ko | ASC | Processed data | ||
Depth-migrated seismic reflection profile GAS36a | 56 Mo | SEGY | Processed data | ||
Velocity model of profile GAS36a | 35 Mo | SEGY | Processed data | ||
Location of profile GAS36a traces | 161 Ko | ASC | Processed data | ||
Depth-migrated seismic reflection profile GAS41 | 27 Mo | SEGY | Processed data | ||
Velocity model of profile GAS41 | 14 Mo | SEGY | Processed data | ||
Location of profile GAS41 traces | 78 Ko | ASC | Processed data |