768258e0-8719-446f-b20f-587725d55774 eng utf8 dataset dataset NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom polardatacentre@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact 2023-03-28 ISO 19115 Geographic Information - Metadata ISO 19115:2003(E) European Petroleum Survey Group (EPSG) Geodetic Parameter Registry 2008-11-12 publication European Petroleum Survey Group EPSGadministrator@iogp.org https://www.epsg-registry.org/ EPSG Geodetic Parameter Dataset The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this online registry. information publisher urn:ogc:def:crs:EPSG::3031 6.18.3 Seismic bathymetry surveys of Subglacial Lake CECs, West Antarctica, 2016 and 2022 2023-03-28 creation 2023-03-28 revision 2023-03-28 publication 2023-03-28 released 1.0 https://doi.org/10.5285/768258e0-8719-446f-b20f-587725d55774 doi GB/NERC/BAS/PDC/01724 https://data.bas.ac.uk/ Please cite this item as: Brisbourne, A., Rivera, A., Zamora, R., Napoleoni, F., Smith, A., Ortega, M., & Uribe Parada, J. (2023). Seismic bathymetry surveys of Subglacial Lake CECs, West Antarctica, 2016 and 2022 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/768258e0-8719-446f-b20f-587725d55774 Subglacial Lake CECs was previously identified using radar profile data. Subglacial Lake CECs lies beneath 2650 m of ice, close to the Ellsworth Mountains at the divide between the Minnesota Glacier and Rutford and Institute Ice Streams in Antarctica. Four seismic reflection profiles were acquired across the lake to determine water column depth and investigate lake bed properties. Shot gathers with 48 channels and a maximum offset of 500 m were recorded. A seismic refraction experiment was undertaken to determine seismic velocities in the firn. Dual frequency and RTK GPS were used to determine shot locations. Seismic surveys indicate a maximum water depth of 301.3 +/- 1.5 m, at the widest part of the lake, with an estimated lake volume of 2.5 +/- 0.3 km3. Imaging of the ice-lake interface indicates topography with slopes of up to 1.9 degrees. This research was supported by the Natural Environment Research Council, British Antarctic Survey (Polar Science for Planet Earth Programme) and Centro de Estudios Cientificos, Valdivia, Chile. No credit. completed Brisbourne, Alex British Antarctic Survey Researcher author Rivera, Andres Universidad de Chile Researcher author Zamora, Rodrigo Centro de Estudios Cientificos Researcher author Napoleoni, Felipe Universidad Austral de Chile Researcher author Smith, Andrew British Antarctic Survey Researcher author Ortega, Marisella Centro de Estudios Cientificos Researcher author Uribe Parada, Jose Andres Centro de Estudios Cientificos Researcher author NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact asNeeded completed EARTH SCIENCE > Solid Earth > Seismology > Seismic Profile EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets theme Global Change Master Directory (GCMD) Science Keywords 2026-01-27 publication 23 Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA) Greenbelt MD United States of America https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords Global Change Master Directory (GCMD) Keywords The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. information publisher Antarctica bathymetry hydrology seismic subglacial lake theme Subglacial Lake CECs, West Antarctica Antarctica place Geology Elevation theme GEMET - INSPIRE themes, version 1.0 2021-01-06 revision otherRestrictions no limitations to public access otherRestrictions no limitations license Open Government Licence v3.0 otherRestrictions Data supplied under Open Government Licence v3.0 otherRestrictions No restrictions apply. doi doi crossReference doi doi crossReference doi doi crossReference url url crossReference url url largerWorkCitation textTable eng utf8 elevation geoscientificInformation inlandWaters -87.9 -87.4 -79.3 -79.2 2016-12-19 2016-12-24 It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk. NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information distributor application/octet-stream text/plain text/csv bytes 843055104 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=768258e0-8719-446f-b20f-587725d55774 WWW:LINK-1.0-http--link Get Data Download data download bytes 843055104 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=768258e0-8719-446f-b20f-587725d55774 WWW:LINK-1.0-http--link Get Data Download data download bytes 843055104 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=768258e0-8719-446f-b20f-587725d55774 WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: In December 2016, three seismic reflection profiles and a seismic refraction profile were acquired across Subglacial Lake CECs (Lines A/C/D). An additional reflection profile was acquired in January 2022 (Line B). Shot points were surveyed in at 240 m intervals using RTK GPS. Twenty metre deep holes were drilled with a hot water drill. Three 150 g Pentolite boosters, end to end and with two detonators (one detonator for line CECD), were lowered to the base of each hole and then backfilled with snow. Shooting was at least 24 hours after backfill. Acquisition was carried out with two 24 channel Geometrics Geode systems using two 24 channel seismic cables. Four-element 40 Hz Georods were buried in-line with the cable to approximately 40 cm depth with the position measured by the cable takeout spacing. Shooting commenced at higher shot point numbers with the cables spread away towards higher shot point values. The spread had a 30 m offset to the first receiver and 10 m spacing between receivers. After each shot, the shot point was moved 240 m towards lower shot point numbers, one cable pulled past the other cable towards lower shot point numbers and the 24 georods redeployed. Four second record length with 8000 Hz sample rate. In 2016 (Lines A/C/D), to ascertain surface elevation, all three reflection profiles were surveyed by driving a continuously recording dual frequency GPS unit along the profile (antenna mounted in a sledge at surface height). In 2022 (Line B), shot points locations were measured with a dual frequency GPS and receiver locations determined by interpolation (and corrected for 2 m survey pole height). A seismic refraction profile was acquired along Profile A centred around CECA_0500 at W087.4529; S79.2439. The firn profile is assumed laterally homogeneous for this purpose and the shot points moved with receivers remaining in position from CECA_0030 to CECA_0500, except to acquire the closely spaced shots. Three shots were acquired to achieve a maximum offset of 930 m. Data collection: Seismic source: 450 g Pentolite in 20 m hot water drill hole, backfilled with snow. Seismic source timing: GPS synchronised trigger. Data logger: 2 x Geometrics Geode 24 ch 24 bit with GPS synchronised trigger. Receivers: 4-element 40 Hz georod sensors on seismic cables with 30 m offset and 10 m spacing. Data quality: Due to a mis-fire, shot CECD_1440 was repeated with the new shot hole located 3 m offset from the original line towards the CECB line. The time interval between drilling to hole backfilling was only 45 minutes. Similarly, shots CECB_1200 and CECB_1440 repeated as initial shot failed. Loaded and shot on the same day. Seismic Reflection Relative uncertainty in source locations is +/- 50 mm. Relative uncertainty in receiver location is +/- 200 mm. Absolute uncertainty in all positions is +/- 2 m. Uncertainty in shot depth +/- 1 m but can be estimated from the surface ghost. Seismic Refraction Relative uncertainty in locations is +/- 25 mm to 50 m then +/- 200 mm onwards. asNeeded completed