Geophysical Survey of McMurdo Ice Shelf to Determine Infrastructure Stability and for Future Planning

• Main Authors: Campbell,Seth, Courville,Zoe, Sinclair,Samantha, Wilner,Joel
• Other Authors: ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH HANOVER United States
• Format: Text
• Language: English
• Published: 2017
• Subjects: Geology; Geochemistry and Mineralogy; Snow; Ice and Permafrost; Active & Passive Radar Detection & Equipment; Brines; Ground penetrating radar; Antarctica; ice; stratigraphy; geophysics; GLACIERS; infrastructure; planning; depth; thickness; dynamics; density; CORE SAMPLING; PERMEABILITY; viscosity; EPOLAR (Engineering for Polar Operations Logistics and Research); Geophysical surveys; Glacial stratigraphy; Glacier ocean interaction; Glaciology; GPR (Ground penetrating radar); mis (McMurdo Ice Shelf); NSF (national science foundation); Snow accumulation; Infrastructure Stability; andrill (Antarctic Geological Drilling); andrill site; ice cores; ice-shelf brine; Englacial structures; fracturing; Antarctic; McMurdo Ice Shelf; Antarc*; Cold Regions Research and Engineering Laboratory; Ice; Ice Shelf; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/AD1036407; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD1036407

Recent surface melting and Antarctic ice-shelf retreat have led to concerns about McMurdo Ice Shelf (MIS) instability, which could threaten research in Antarctica. Researchers at the U.S. Army Cold Regions Research and Engineering Laboratory collected approximately 1300 km of ground-penetrating radar (GPR) profiles over MIS, using frequencies between 40 and 400 MHz, to determine extent, continuity, and depth of the brine and ice-shelf thickness; to map englacial horizons; and to locate any structural features that may suggest shelf instability. We suggest that brine, sediment-rich ice, and a rough direct coupling attenuates the signal in this region of MIS. Results show no major englacial features that raise concerns for shelf stability; however, two locations are worthy of continued monitoring from an operational and safety perspective. The first location is a prior Antarctic Geological Drilling (ANDRILL) site from 2006; the infrastructure established during ANDRILL operations appears to have actually influenced ice dynamics in the region. The second location is a long-term rift located near the ice shelf-sea ice edge. This study supports prior results that suggest that repeat high-resolution, ground-based GPR is useful for reconstructing ice-shelf history through analysis of imaged englacial and basal structures.