Date (Creation)

2023-03-28

Date (Revision)

2023-03-28

Date (Publication)

2023-03-28

Date (released)

2023-03-28

Edition

1.0

Unique resource identifier

https://doi.org/10.5285/768258e0-8719-446f-b20f-587725d55774

Codespace

doi

Unique resource identifier

GB/NERC/BAS/PDC/01724

Codespace

https://data.bas.ac.uk/

Other citation details

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

Credit

No credit.

Status

Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Antarctic Survey	Brisbourne, Alex		Author
Universidad de Chile	Rivera, Andres		Author
Centro de Estudios Cientificos	Zamora, Rodrigo		Author
Universidad Austral de Chile	Napoleoni, Felipe		Author
British Antarctic Survey	Smith, Andrew		Author
Centro de Estudios Cientificos	Ortega, Marisella		Author
Centro de Estudios Cientificos	Uribe Parada, Jose Andres		Author
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Point of contact

Maintenance and update frequency

As needed

Maintenance note

Completed

Global Change Master Directory (GCMD) Science Keywords

• EARTH SCIENCE > Solid Earth > Seismology > Seismic Profile
• EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets

Theme

• Antarctica

• bathymetry

• hydrology

• seismic

• subglacial lake

Place

• Subglacial Lake CECs, West Antarctica Antarctica

GEMET - INSPIRE themes, version 1.0

• Geology
• Elevation

Access constraints

Other restrictions

Other constraints

no limitations to public access

Access constraints

Other restrictions

Other constraints

no limitations

Use constraints

License

Other constraints

Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

Data supplied under Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

No restrictions apply.

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

url

Codespace

url

Association Type

Cross reference

Unique resource identifier

url

Codespace

url

Association Type

Larger work citation

Spatial representation type

Text, table

Language

English

Character set

UTF8

Topic category

• Elevation
• Geoscientific information
• Inland waters

Begin date

2016-12-19

End date

2016-12-24

Supplemental Information

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.

Title

European Petroleum Survey Group (EPSG) Geodetic Parameter Registry

Date (Publication)

2008-11-12

Cited responsible party

Organisation name	Individual name	Electronic mail address	Role
European Petroleum Survey Group		EPSGadministrator@iogp.org	Publisher

Unique resource identifier

urn:ogc:def:crs:EPSG::3031

Version

6.18.3

Hierarchy level

Dataset

Statement

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.

Metadata

File identifier

768258e0-8719-446f-b20f-587725d55774 XML

Metadata language

English

Character set

UTF8

Hierarchy level

Dataset

Hierarchy level name

dataset

Date stamp

2023-03-28

Metadata standard name

ISO 19115 Geographic Information - Metadata

Metadata standard version

ISO 19115:2003(E)

Metadata author

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		polardatacentre@bas.ac.uk	Point of contact