Methodology:

The purpose of site visits was to service seismic stations of the UKANET seismic network near Pine Island Glacier, and to locate and raise equipment depoted in January 2016 at Mt Murphy (on the western margin of the Thwaites-Haynes Glacier catchment). The seismic stations are powered by solar energy during the summer. At installation, the heights of the solar panels above the snow surface were recorded using a tape measure. Servicing entailed raising the seismometer back toward the surface via vertical shafts dug with shovels. By repeating the measurement of the solar panel height above (or below, following complete burial) the snow surface, the total depth of snow that had fallen during the period of approximately 11 months between initial deployment and servicing was determined.

The equipment depoted at Mt Murphy in early 2016 became completely buried by snow during the subsequent 11 months. The green tarpaulin covering the depot was eventually located by digging a vertical shaft through which the snow depth to the base of the depot was measured. Further details are provided in the associated publication.

Data quality:

The measurement uncertainty is no more than 10 cm. The time period over which the measurements were collected is short, thus uncertainties related to internal ice deformation, glacier flow and drift are likely to be minimal.