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

FileSizeFormatProcessingAccess
Depth-migrated seismic reflection profile GAS30d
52 MoSEGYProcessed data
Velocity model of profile GAS30d
29 MoSEGYProcessed data
Location of profile GAS30d traces
110 KoASCProcessed data
Depth-migrated seismic reflection profile GAS31a
56 MoSEGYProcessed data
Velocity model of profile GAS31a
30 MoSEGYProcessed data
Location of profile GAS31a traces
160 KoASCProcessed data
Depth-migrated seismic reflection profile GAS33c
27 MoSEGYProcessed data
Velocity model of profile GAS33c
15 MoSEGYProcessed data
Location of profile GAS33c traces
76 KoASCProcessed data
Depth-migrated seismic reflection profile GAS34a
28 MoSEGYProcessed data
Velocity model of profile GAS34a
15 MoSEGYProcessed data
Location of profile GAS34a traces
80 KoASCProcessed data
Depth-migrated seismic reflection profile GAS34b
44 MoSEGYProcessed data
Velocity model of profile GAS34b
17 MoSEGYProcessed data
Location of profile GAS34b traces
126 KoASCProcessed data
Depth-migrated seismic reflection profile GAS36a
56 MoSEGYProcessed data
Velocity model of profile GAS36a
35 MoSEGYProcessed data
Location of profile GAS36a traces
161 KoASCProcessed data
Depth-migrated seismic reflection profile GAS41
27 MoSEGYProcessed data
Velocity model of profile GAS41
14 MoSEGYProcessed data
Location of profile GAS41 traces
78 KoASCProcessed data
How to cite
Thomas Yannick, Marsset Bruno, Dupont Pauline, Ker Stephan, Riboulot Vincent (2023). Depth-migrated High Resolution seismic reflection profiles and interval velocity models in the western Black Sea. SEANOE. https://doi.org/10.17882/96701

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