Hammer plate seismic on the Shackleton Ice Shelf - 2023-24

Raw active source seismic data collected using the hammer and plate method at two sites on the margin of the Shackleton Ice shelf, close to the Denman Glacier Tongue. The data were collected in conjunction with radar data (metadata record) to optimally locate a hot water drilled borehole by providing a measure of the ice shelf thickness and the depth to the ocean floor beneath the ice shelf.

The survey involved laying out an array of 48 geophones along a line 470 m long with geophones spaced every 10m. The geophones were pushed into the snow surface to the same level. The source of seismic energy is simply a thick plastic plate struck by a sledgehammer which is located at the survey line mid-point. Two point measurements were collected, HWD_01 and HWD_02.

HWD_01
Date:16/12/2023 Timing: 1300 - 1700 Location: Shackleton Ice Shelf close to the Denman Glacier margin Coordinates: -66.230357, 98.735936 Team: Sarah Thompson, Katie Miles, Nick Morgan Weather: Some high cloud, low wind, good visibility Site notes: Very soft snow. Equipment: 48 channel Geometrics Geode Seismograph communicating with a laptop via ethernet cable using Geometrics Seismodule Controller Software Version 11.1.69.0 (Geometrics Inc., 2014). Sampling interval: 62.5 microseconds Window length: 2 seconds Survey layout: 2 x 235 m cables (10 m spacing), geophones all set into surface by pushing into the snow. Bearing of seismic line: 266 degrees Geophones: 1-24 to East and 24-28 to West of centre point Shot point: Midpoint of survey line. Survey collected in two halves due to software issues, ~20 hammer blows per half, all hammer blows carried out by Nick Morgan.

Files included *.dat - raw data files each containing seismic record from single shot Geophones 1-24: 1000.dat – 1021.dat Geophones 25-48: 1022.dat – 1042.dat

HWD_02 - Date: 26/12/2023 Timing: 1530 - 1800 Location: Shackleton Ice Shelf close to the Denman Glacier margin Coordinates: -66.232110, 98.738019 Team: Sarah Thompson, Katie Miles, Madi Rosevear, Nick Morgan Weather: Some high cloud, low wind, good visibility Site notes: Very soft snow. Equipment: 48 channel Geometrics Geode Seismograph communicating with a laptop via ethernet cable using Geometrics Seismodule Controller Software Version 11.1.69.0 (Geometrics Inc., 2014). Sampling interval: 62.5 micro seconds Window length: 2 seconds Survey layout: 2 x 235 m cables (10 m spacing), geophones all set into surface by pushing into the snow. Bearing of seismic line: 296 degrees Geophones: 1-24 to East and 24-28 to West of midpoint Shot point: Midpoint of survey line. Survey collected in two halves due to software issues, 20 hammer blows per half, all hammer blows carried out by Nick Morgan.

Files included *.dat - raw data files each containing seismic record from single shot Geophones 1-24: 1000.dat – 1001.dat Geophones 25-48: 2000.dat – 2018.dat and 2020.dat - 2021.dat