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  • Binary Object; Binary Object (File Size); Binary Object (Media Type); Date/Time of event; Date/Time of event 2; Event label; four components; GI-gun; James Cook; JC152; JC152_OBS-1; JC152_OBS-10; JC152_OBS-11; JC152_OBS-12; JC152_OBS-13; JC152_OBS-14; JC152_OBS-15; JC152_OBS-16; JC152_OBS-17; JC152_OBS-18; JC152_OBS-19; JC152_OBS-2; JC152_OBS-20; JC152_OBS-21; JC152_OBS-22; JC152_OBS-23; JC152_OBS-24; JC152_OBS-25; JC152_OBS-3; JC152_OBS-4; JC152_OBS-5; JC152_OBS-6; JC152_OBS-7; JC152_OBS-8; JC152_OBS-9; Latitude of event; Longitude of event; OBS; ocean bottom seismometer; Ocean bottom seismometer; Scanner Pockmark; Scanner pockmark, North Sea; S-wave splitting; wide-angle data  (1)
  • high resolution images  (1)
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  • 1
    Publication Date: 2024-04-20
    Description: The three-dimensional wide-angle active source seismic dataset was acquired during the CHIMNEY seagoing expedition (RRS James Cook – JC152 experiment; August – September 2017), at the Scanner pockmark, an active fluid flow structure in the North Sea. The aim of the data collection was to understand the structure and the physical properties below this methane-venting seafloor depression. The data were acquired using two GI-guns in harmonic mode (2x210 cu. in.) and 25 four-component Ocean Bottom Seismometers recording at a sampling rate of 4 kHz. The shooting interval was 8 s, equivalent to 18.5 m at the mean vessel speed of 4.5 kn. Additional seismic reflection data acquired during JC152 are used for comparison with the ocean bottom seismometer data. Three sub-bottom profiler profiles, one horizon surface (Base of the Witch Ground formation) and one multi-channel profile acquired with a surface sparker are used for comparison. The sub-bottom profiler data were acquired using a chirp sweep lasting 0.035 s, with a bandwidth of 2.8-6 kHz, and a central frequency of 4.4 kHz. These profiles have a trace spacing of 2.5 m and a vertical resolution of 〈 15 cm. The base of the Witch Ground formation is interpreted as a surface from over 100 SBP profiles and the surface attributes are used for comparison with OBS recordings. The Squid surface sparker data were acquired with a 80-1800 Hz source and 2 s shot interval (~4.6 m at 4.5 kn), and were recorded on a multi-channel streamer.
    Keywords: Binary Object; Binary Object (File Size); Binary Object (Media Type); Date/Time of event; Date/Time of event 2; Event label; four components; GI-gun; James Cook; JC152; JC152_OBS-1; JC152_OBS-10; JC152_OBS-11; JC152_OBS-12; JC152_OBS-13; JC152_OBS-14; JC152_OBS-15; JC152_OBS-16; JC152_OBS-17; JC152_OBS-18; JC152_OBS-19; JC152_OBS-2; JC152_OBS-20; JC152_OBS-21; JC152_OBS-22; JC152_OBS-23; JC152_OBS-24; JC152_OBS-25; JC152_OBS-3; JC152_OBS-4; JC152_OBS-5; JC152_OBS-6; JC152_OBS-7; JC152_OBS-8; JC152_OBS-9; Latitude of event; Longitude of event; OBS; ocean bottom seismometer; Ocean bottom seismometer; Scanner Pockmark; Scanner pockmark, North Sea; S-wave splitting; wide-angle data
    Type: Dataset
    Format: text/tab-separated-values, 213 data points
    Location Call Number Limitation Availability
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  • 2
    ISSN: 1573-0581
    Keywords: Chirp profilers ; high resolution images ; archaeological case study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Chirp sub-bottom profilers produce high-resolution images of the near-surface. An attribute of the sea-bed reflection in chirp data are fluctuations in polarity between adjacent traces. Two models are proposed and presented to explain this: the first incorporates changes in an acoustic impedance gradient at the sea bed; the second uses changes in the thickness of the uppermost sediment layer. Mixing of adjacent traces produces a consistent polarity for the sea-bed reflector. Reflection coefficients are calculated, using amplitude information derived from single-traces, and polarity information from trace mixing, with application to a marine archaeological case study. The reflection coefficient calculated for the top of a buried 18th century wooden wreck is -0.26.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
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