Anisotropy and structure of the Priestley Glacier shear margin, Antarctica

• Main Authors: David Prior, Huw Horgan
• Format: Dataset
• Language: unknown
• Published: International Federation of Digital Seismograph Networks 2019
• Subjects: Priestley; David Glacier; Priestley Glacier; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.7914/sn/zb_2019; https://www.fdsn.org/networks/detail/ZB_2019/

We aim to use seismology to constrain the large scale crystallographic preferred orientation (CPO = crystal orientation fabric) across the Priestley Glacier shear margin and satellite data to model the strain history that has resulted in the CPO. We will compare these data to results of thermo-mechanical forward models to establish whether strain dependent flow laws make a critical difference in controlling the shear margin mechanics and to define other measurements needed to test ice flow laws more completely. This will be the second field season operating on the Priestley (Original application 2018 was for the David Glacier: site location changed for safety reasons). In 2018 we had good coverage of shallow ray paths, The focus in 2019 will be to increase the areal coverage of the survey and to include steeper ray-paths between surface sources and borehole instruments. Receiver stations will comprise surface and borehole 3-component geophones. Source and receiver positions have been chosen to generate sufficient ray paths to distinguish likely CPOs using velocity anisotropy (P,S) and S-wave splitting on direct arrivals from explosive sources. The site is a blue ice site and sources and receivers will be frozen to the ice for maximum coupling and minimum attenuation. We plan to have 5 arrays of receivers, each comprising 24 channels recorded on one GEODE. We already have three GEODES. We are looking to borrow two GEODES from IRIS Pasccal (We only need the GEODES and tehir cables. We do not need any geophones).