Date (Creation)

2020-06-29

Date (Revision)

2020-06-29

Date (Publication)

2020-06-29

Date (released)

2020-06-29

Edition

1.0

Unique resource identifier

https://doi.org/10.5285/8cdf7941-f13b-4237-b921-05a6c6cde40a

Codespace

doi

Unique resource identifier

GB/NERC/BAS/PDC/01351

Codespace

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

Other citation details

Please cite this item as: Lim, M., & Martin, J. (2020). Geophysical survey of Peninsula Point, NWT, Canada, using Tromino 3G ENGY instruments, 2019-07-31 - 2019-08-03 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/8cdf7941-f13b-4237-b921-05a6c6cde40a

Credit

No credit.

Status

Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
Northumbria University	Lim, Michael		Author
Northumbria University	Martin, James		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 > Cryosphere > Frozen Ground > Permafrost
• EARTH SCIENCE > Cryosphere > Snow/Ice > Permafrost
• EARTH SCIENCE > Land Surface > Frozen Ground > Permafrost
• EARTH SCIENCE > Solid Earth > Seismology > Seismic Surface Waves

Theme

• Geophysical Survey

• Massive Ice

• Passive Seismic

• Permafrost

Place

• Peninsula Point, Northwest Territories, Canada Arctic

GEMET - INSPIRE themes, version 1.0

• Meteorological geographical features
• Land cover
• Geology

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

This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/

Use constraints

Other restrictions

Other constraints

These data are governed by the NERC data policy and supplied under Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

No restrictions apply.

Unique resource identifier

url

Codespace

url

Association Type

Cross reference

Spatial representation type

Text, table

Language

English

Character set

UTF8

Topic category

• Elevation
• Environment
• Geoscientific information

Begin date

2019-07-31

End date

2019-08-03

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:

Passive seismic surveys have been conducted in order to map and characterize the spatial distribution of subsurface layers across the site at Peninsula Point. Three-dimensional wave signals within the earths sub-surface propagate through the near surface layers and notable differences between amplitudes of horizontal and vertical motions are caused by acoustic impedance contrasts at layer boundaries. The spectral ratio of horizontal over vertical responses exhibit resonance frequencies (fr) that can be directly linked to the layer thickness (h). The layer thicknesses are estimated by the quarter wavelength resonance approximation. Measurements of visible contact layer depths exposed in permafrost cliff sections adjacent to a set of control reading locations have been used to characterize relative acoustic impedance contrast signatures and to calculate shear wave velocity (Vs) through each of the main material layers (see supporting information). This has enabled the determination of two distinct high frequency signal peaks associated with specific ground layer controls.

A single peak in the resonance frequency (usually around 20 Hz) denoted active layer or slurry contact directly onto massive ice, whereas traces with a high frequency peak around 30 - 50 Hz (usually with additional lower frequency peaks of 1 - 5 Hz) represented a permafrost to ice contact. Sub-divisions were also identified: Group 1 = single distinct peak representing a shallow contact directly on to ice (no lower frequency acoustic impedance contrast); Group 2 = large peak then a secondary lower peak that corresponds with the permafrost-ice contact and then the base of the massive ice (from boreholes we know this to mostly a sand layer) respectively; Group 3 = a muted high frequency peak that then curves up to a low frequency base line; Group 4 = two comparable peaks, which may indicate a lower contrast in the impedance so potentially frozen sand layers, although there is no validation for this interpretation. Once the impedance contrast signatures were classified, the following formula was applied to calculate and validate layer boundary depths (h):

h = Vs / 4fr

A shear-wave velocity of 920 ms-1 for the permafrost was determined from cliff outcrop data at the site and was used to derive depth to the massive ice contact. Validation sites have also been used to make sure that layer properties were sufficiently consistent over the survey area (see supporting information) and active layer probe depths have been used to map ice surface where it rose to very near the ground surface (and hence no permafrost was present). The 2018 massive ground ice surface has been interpolated to form a massive ice surface relative to sea-level (Ice_Surface.tif).

Data collection:

Tromino® 3G ENGY instruments have been used to record three component accelerometer measurements of ambient noise and have been processed in Grilla Software.

Data quality:

Surface to ice surface measurements from exposed ice cliffs have been used to calibrate and validate the shear wave velocities used to derive surface boundaries.

Metadata

File identifier

8cdf7941-f13b-4237-b921-05a6c6cde40a XML

Metadata language

English

Character set

UTF8

Hierarchy level

Dataset

Hierarchy level name

dataset

Date stamp

2020-06-29

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