99f0d269-d8fa-48e0-89e6-358486d82330 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 2021-01-19 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 Downhole distributed acoustic seismic profiles at SkyTrain Ice Rise, West Antarctica, January 2020 2021-01-19 creation 2021-01-19 revision 2021-01-19 publication 2021-01-19 released 1.0 https://doi.org/10.5285/99f0d269-d8fa-48e0-89e6-358486d82330 doi GB/NERC/BAS/PDC/01458 https://data.bas.ac.uk/ NE/G014159/1 award NE/G013187/1 award Please cite this item as: Brisbourne, A., & Kendall, M. (2021). Downhole distributed acoustic seismic profiles at SkyTrain Ice Rise, West Antarctica, January 2020 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/99f0d269-d8fa-48e0-89e6-358486d82330 A distributed acoustic sensing (DAS) experiment was undertaken at SkyTrain Ice Rise in the Weddell Sea Sector of West Antarctica. The aim was to evaluate the use of DAS technology using existing infrastructure and for delineating the englacial fabric to improve our understanding of ice sheet history in the region. Three walkaway profiles were acquired at 45 degree intervals using a hammer and plate source. Both direct and reflected P- and S-wave energy, as well as surface wave energy, are observed using a range of source offsets recorded using fibre optic cable. Significant noise results from the cable hanging untethered in the borehole. At greater depth, where drilling fluid is present, signal strength is sufficient to measure seismic interval velocities and attenuation. Fieldwork was part of the BEAMISH Project (NERC AFI award numbers NE/G014159/1 and NE/G013187/1). John Michael Kendall was supported by additional funding from NERC award No. CASS-166. The Skytrain borehole and fibre optic cable are part of the University of Cambridge WACSWAIN Project (EU Horizon 2020 agreement No. 742224). No credit. completed Brisbourne, Alex British Antarctic Survey Researcher author Kendall, Mike University of Oxford 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 > Cryosphere > Glaciers/Ice Sheets > Glacier Motion/Ice Sheet Motion 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 Distributed acoustic sensing - DAS Ice rise Vertical Seismic Profile - VSP theme SkyTrain Ice Rise, West Antarctica Antarctica place 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 This data is supplied under Open Government Licence v3.0 otherRestrictions No restrictions apply. url url crossReference doi doi crossReference url url largerWorkCitation url url largerWorkCitation textTable eng utf8 environment geoscientificInformation -78.5448 -78.5448 -79.7411 -79.7411 2020-01-24 2020-01-24 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/netcdf application/x-hdf application/octet-stream text/plain bytes 93200790323 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=99f0d269-d8fa-48e0-89e6-358486d82330 WWW:LINK-1.0-http--link Get Data Download data download bytes 93200790323 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=99f0d269-d8fa-48e0-89e6-358486d82330 WWW:LINK-1.0-http--link Get Data Download data download bytes 93200790323 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=99f0d269-d8fa-48e0-89e6-358486d82330 WWW:LINK-1.0-http--link Get Data Download data download bytes 93200790323 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=99f0d269-d8fa-48e0-89e6-358486d82330 WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: In the 2018/19 Antarctic field season, a 651 m ice core was collected at Skytrain Ice Rise, West Antarctica. A multi-mode fibre optic cable was deployed to allow DTS temperature measurements. In January 2020 the site was revisited to conduct a VSP experiment using the existing fibre optic cable and a Silixa iDAS interrogator unit with GPS timing. A 1.0 kVA petrol generator was used to power the interrogator unit. The interrogator was housed in a tent to protect it from the wind and maintain a working temperature. Data were recorded at 8000 Hz sampling frequency. Strain rate measurements were made at 1 m intervals along the fibre but with an effective resolution of 10 m due to the "gauge length" or strain rate averaging process. The fibre optic cable is 600 m long, with 595 m deployed down the borehole, and includes a minibend where an identical length of fibre within the cable is spliced and returned to the surface, enabling two measurements to be made at each depth and a raw data length of 1200 m. The DAS method measures longitudinal strain. Therefore, with the fibre optic cable vertical, only the vertical strain component of seismic waves propagating past the fibre is measured. Three walkaway profiles with seismic sources on the snow surface were acquired at 45 degrees to one another. Line names reference the orientation with respect to magnetic north. A 4.5 kg sledgehammer with a rigid polyethylene impact plate stamped into the snow surface acted as the energy source. Profiles were acquired out to 600 m offset from the borehole with hammer blows at 50 m intervals. Two hammer blows were made at each shot point out to 350 m and four hammer blows from 400 m and beyond. The interrogator unit recorded in continuous mode with shot times derived from impulsive arrivals on a continuous 1000 Hz sampled geophone recording made adjacent to the hammer plate. The fibre optic cable is hanging freely in the borehole, not frozen to the walls. Drilling fluid remains in the borehole from the previous season, filling approximately the lower half of the hole. The upper half of the fibre therefore hangs freely in air and is poorly coupled to the walls of the borehole. The lower half of the fibre is supported in the drilling fluid. Data collection: Seismic source: 4.5 kg hammer with rigid polyethylene impact plate. Seismic source timing: Reftek RT130 (serial no. bcbf) with 3-component geophone located adjacent to the hammer plate recording at 1000 sps. DAS: Silixa iDAS interrogator (serial number - 15040) with GPS timing recording at 8000 sps with 10 m gauge length. Fibre optic cable: 2x50 μm multimode fibre 600 m long with minibend. All shots within a 600 m radius of the borehole. DAS data were recorded at 8000 Hz sampling frequency. Strain rate measurements were made at 1 m intervals along the fibre but with an effective resolution of 10 m due to the "gauge length" or strain rate averaging process. Shot times are derived from a geophone located adjacent to the plate, recorded at 1 ms sample interval. Raw data from the geophone located at the shot point are provided for verification. Shot locations were surveyed in from the borehole location using compass and tape measure (Line ST130) and handheld GPS (Lines ST040 & ST085) giving a location uncertainty of +/-5 m. Data quality: The fibre optic cable is deployed in an open borehole with drilling fluid in the lower half (approximately). The cable is not frozen-in to the hole or to the wall of the hole. The signal in the upper half, which hangs in air, is therefore dominated by harmonic noise and weak coupling. Signal from the lower half, which sits in the drilling fluid, is stronger and noise levels are lower. asNeeded completed