Seismic measurements of the ice draught and seabed elevation across the southern and western Ronne Ice Shelf, 1994-95
GB/NERC/BAS/PDC/02228
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Summary
Abstract:
During the 1994-95 Austral summer, seismic measurements for ice draught and seabed elevation were made across the southern and western Ronne Ice Shelf, West Antarctica. Point measurements were made at 15 km (average) intervals along a 2300 km zig-zag traverse. Seismic sources were explosives in 4 m deep hand-drilled shot holes. In addition, two seismic refraction measurements were taken at each of five selected measurement sites. These data were not archived at the time, and these data represent a best effort at collating data files and the field report to determine the data provenance.
Data were collected by the British Antarctic Survey.
Keywords:
West Antarctica, bathymetry, ice shelf, ice stream, seismic
Citation
Brisbourne, A., Hoeppner, L., Johnson, M., Smith, A., & Sweeny, J. (2026). Seismic measurements of the ice draught and seabed elevation across the southern and western Ronne Ice Shelf, 1994-95 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/4629cb1c-126e-46db-a874-9b7b969997d4
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ASSOCIATED DATA SET(S)
REFERENCE MATERIALS
- https://doi.org/10.1017/S0954102097000254
- https://doi.org/10.1029/2000JB900449
- https://nora.nerc.ac.uk/id/eprint/541891
Constraints
| Access Constraints: | No restrictions apply |
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| Use Constraints: | This data is governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v.3 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ |
Basic Information
| Creation Date: | 2026-06-18 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Alex Brisbourne |
| Role(s) | Investigator, Technical Contact |
| Organisation | British Antarctic Survey |
| Name | Laura Hoeppner |
| Role(s) | Investigator |
| Organisation | Alfred Wegener Institute for Polar and Marine Research |
| Name | Mark R Johnson |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Andrew M Smith |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | John Sweeny |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
Additional Information
| Reference: | Johnson, Mark R., 1995. 'Ronne Ice Shelf Spot Depth Seismics 94/95'. Reproduced courtesy of the British Antarctic Survey Archives Service. Archives ref. AD6/2R/1994/S2. Copyright UK Research and Innovation. https://nora.nerc.ac.uk/id/eprint/541891 Johnson MR, Smith AM. Seabed topography under the southern and western Ronne Ice Shelf, derived from seismic surveys. Antarctic Science. 1997;9(2):201-208. doi:10.1017/S0954102097000254 Lythe, M. B. and Vaughan, D. G.: BEDMAP: A new ice thickness and subglacial topographic model of Antarctica, Journal of Geophysical Research: Solid Earth, 106, 11335-11351, https://doi.org/10.1029/2000JB900449, 2001. Lythe, M., Vaughan, D., & BEDMAP 1 Consortia. (2023). BEDMAP1 - Ice thickness, bed and surface elevation for Antarctica - gridding products (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/908BB17F-467C-42BF-AE00-F03BB0FEEA23 |
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| Quality: | Station positions were determined using GPS satellite position fixes and have an estimated horizontal rms error of 120 m. Of this, 100 m originates from the accuracy degradation by the US Defense Department selective availability program. Altitude error was estimated at 100 m. At some sites, the ice-base reflection was partly obscured by ground-roll. Occasionally this made identification of the ice-base difficult. In these cases, multiple reflections from within the ice and the water column, which arrive much later than the ground-roll, were sometimes useful in identifying arrivals. If a reflection has been identified correctly, then the travel times of the multiple reflections are predictable. In some cases, band-pass filters were sufficient to remove the ground-roll. The poorest records were acquired close to shear margins and grounding lines, where relatively high ambient noise levels and extra arrivals from natural acoustic energy or out-of-plane reflections were common. In these cases, the application of an automatic gain control (AGC) filter to compensate for absorption and spherical divergence of the seismic waves in the ice was usually sufficient to confirm the identification of the various arrivals. Following close-scrutiny of the poor seismic records, and the utilisation of simple AGC or band-pass filters and multiple reflections, it was possible to identify ice-base and seabed reflections (or ice-bed reflections for grounded ice) at all the stations. Here, we have assigned data files to locations by comparing date-time stamps in the original file header with the narrative and additional details in the field report and respective publication, as well as previously measured ice draught and bed depths. We cannot guarantee that this assignment is without errors, and mistakes may be present in this interpretation. No geometry headers are populated in the SEG-Y files. Average measurement spacing is 15 km. Error in ice thickness is +/- 9 m. Error in seabed elevation is +/- 15 m. Please note that the time reference associated with the dataset is uncertain. The only explicit indication in the associated report (https://nora.nerc.ac.uk/id/eprint/541891) is the gravimeter plot labelled 'Local'; however, data acquisition was conducted using GPS, which typically operates in UTC. It is therefore likely that timestamps originate from the data recorder header (commonly UTC), though they may have been synchronised to the acquisition computer, potentially set to local time. As no definitive documentation confirms the time standard, the temporal reference should be treated as ambiguous. |
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| Lineage/Methodology: | Point measurements were made at 15 km (average) intervals along a 2300 km zig-zag traverse. Station positions were determined using GPS satellite position fixes. For each reflection seismic measurement, a 4 m deep shot hole was drilled using a hand operated ice-corer. The holes were charged with 100-300 g of high explosive and then backfilled with snow. Shots were detected by twenty-four vertically orientated geophones at 10 m intervals from 30 to 260 m from the source. The geophones were buried at a depth of around 0.4 m both to ensure a firm coupling with the snow and protection from wind noise. The seismic signal was recorded on a 24-channel BISON 9024 seismograph at a sample interval of 0.25 ms. Analogue filters were applied at recording (Low-cut 4 Hz and High-cut 1 kHz) with a record delay (recorded in the file header) and record length 1.5 to 2.5 s. All pre-amplifier gains were set to high. Record lengths were up to two and a half seconds so that primary arrivals from the ice-base and seabed, as well as later multiple arrivals were recorded. These multiples are a useful aid in the correct identification of the primary arrivals. The seismic reflection data required little subsequent processing. Most of the records were of sufficient quality for the ice-base and seabed reflections to be easily identified as high-amplitude events. The raw field data are made available here. No data processing has been applied other than conversion from BISON format to SEG-Y. Seismic refraction measurements were made at five sites (D2, H1, O1, T4, V7). Derived surface elevation, ice draught and seabed elevation measurements are provided (Ice Thickness = Ice elevation + Ice draught). These are the values calculated and published by Johnson and Smith (1997), where the methods are described in full. At the time, the data were not submitted to a data centre or specifically archived for future use. However, the data are referenced in Bedmap (Lythe and Vaughan, 2001). The metadata presented here are therefore a "best effort" at interpreting the contemporaneous field report and published manuscript, and file name and headers including a time stamp. Site names used in Johnson and Smith (1997) do not map directly to filenames. The recorded GPS coordinates are mapped to profile letter identifiers (referred to as waypoints in the field report - https://nora.nerc.ac.uk/id/eprint/541891) with sequential numbering as used in field report R/1994/S2 but not the sequential station numbers reported in Johnson and Smith (1997). There is no recorded direct assignment of seismic data file names to locations or coordinates. Therefore, using the field report and published manuscript, as well as the derived/reported ice draught and bed depths, we have mapped the filenames to the best of our ability to the waypoint and site numbers used in the BAS field report (R/1994/S2) and the profile and sequential number used in Johnson and Smith (1997). |
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Locality
| Temporal Coverage: | |
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| Start Date | 1994-12-06 |
| End Date | 1995-02-18 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -77.504 |
| Northernmost | -50.502 |
| Longitude | |
| Westernmost | -82.167 |
| Easternmost | -76.817 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Data Resolution: | |
| Latitude Resolution | N/A |
| Longitude Resolution | N/A |
| Horizontal Resolution Range | 10 km - < 50 km or approximately .09 degree - < .5 degree |
| Vertical Resolution | N/A |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Evans Ice Stream |
| Location | Antarctica |
| Detailed Location | Ronne Ice Shelf |
Instrumentation
| Sensor(s): |
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| Data Collection: | The seismic signals were recorded on a 24-channel BISON 9024 seismograph. Reflection surveys: sample interval of 0.25 ms with twenty-four vertically orientated geophones at offsets of between 30-260 m from the source at 10 m intervals. Shallow refraction surveys: sample interval 0.1 ms with following geometry: Shot 1 - 20 cm depth into offsets of 1,2.5,5,.5,10,12.5,15,20,25,30,35,40,45,50,60,70...140,150 m; Shot 2 - 1 m depth for offsets from 150 to 380 m at 10 m intervals. Site locations were measured with a Garmin 75 GPS unit. All elevations are assumed to be referenced to the WGS-84 ellipsoid. |
Storage
| Distribution: | |
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| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 54 MB |
| Distribution Format | N/A |
| Fees | N/A |
| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 22 kB |
| Distribution Format | ASCII |
| Fees | N/A |
| Data Storage: | This dataset consists of: - seismic shot gathers in SEG-Y IBM format (161 files ~54 MB). Please note that no geometry headers are populated in the SEG-Y files. - Location, surface elevation, ice draught and seabed elevation for each stations in CSV format (1 file ~22kB) |