Geological Survey of Canada Offshore Single Channel Seismic Reflection Data, Beaufort Shelf and Slope
High resolution seismic reflection data are collected by deploying acoustic sources (operating in the frequency range centered on 3.5 kHz) to provide a short duration sound pulse that can penetrate the seafloor and sub-seafloor sediments. The sound pulses are reflected by acoustic impedance contrast...
| Main Authors: | , |
|---|---|
| Format: | Dataset |
| Language: | English |
| Published: |
Canadian Cryospheric Information Network
2015
|
| Subjects: | |
| Online Access: | https://dx.doi.org/10.5443/12058 https://www.polardata.ca/pdcsearch/?doi_id=12058 |
| Summary: | High resolution seismic reflection data are collected by deploying acoustic sources (operating in the frequency range centered on 3.5 kHz) to provide a short duration sound pulse that can penetrate the seafloor and sub-seafloor sediments. The sound pulses are reflected by acoustic impedance contrasts back to the receiver of seismic system. An ensemble of sequential echoes forms what is called a seismic section, essentially a two-dimensional time slice or image of acoustic discontinuities in the subsurface. These acoustic images are interpreted by a mapping geologist or geophysicist to infer geological characteristics of the subsurface. Typically these high resolution systems are used to delineate seabed and sub-seabed geological structure down to depths of less than 50m below the seabed. At the Geological Survey of Canada, a variety of high resolution seismic systems are used to map the sub-seabed. Those collected with support from AANDC (Aboriginal Affairs and Northern Development Canada) through the BREA program (Beaufort Regional Environmental Assessment) include only high-frequency swept frequency chirp systems that can resolve sub-metre structure (Knudsen 3.5kHz). These data have been collected in digital formats (generally the SEGY international standard), and are made publically available through various portals including the Polar Data Catalogue, Natural Resources Canada, the University of New Brunswick Ocean Mapping Group and Laval University. The NRCan distribution process is in development and will likely change by April 2015. The supplied url or FTP will likely be little changed; currently it houses only the older (scanned format) profile data on a cruise by cruise basis but this will also include digitally collected data, including the BREA - supported collections. : Purpose: Marine high resolution seismic reflection data are used to address a multitude of issues in the offshore ranging from the recognition and assessment of hazards to offshore development, the assessment of benthic habitat, oil and gas pipeline planning and routing, the understanding of sediment transport processes, to the study of general geological processes, evolution and history. : Summary: This dataset includes sonar profiles collected in the Beaufort Sea during several offshore surveys conducted from the ArcticNet research vessel "Amundsen". Related GSC data themes in the Polar Data Catalogue include information on seabed samples, images of seabed topography (shape and water depth) from multibeam sonar and sub-seabed sonar data capable of imaging geological information at and up to 50m below the seabed. These data are used collectively to evaluate the nature of the seabed in terms of the various past and present processes which lead to the present environment and its dynamics. Some of the relevant concerns are the nature of the seabed in terms of stability for life-forms, its strength for possible engineering installations, and the likelihood of change in the seabed with natural environmental influences. These influences can include past climate effects such as glacier cover and its ancient shaping of the seabed landscape and its mud and sand deposits, storms, currents, sea-ice impact on the seabed, possible presence and change related to shallow natural gas below the seabed, permafrost at and below the seabed and its natural changes, possible effects of earthquakes on the stability of that sediment, including marine landslides. |
|---|