Thermally induced icequakes detected on blue ice areas of the East Antarctic ice sheet

• Published in: Annals of Glaciology
• Main Authors: Denis Lombardi, Irina Gorodetskaya, Guilhem Barruol, Thierry Camelbeeck
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2019
• Subjects: Antarctic glaciology; blue ice; ice rheology; ice temperature; seismology; Meteorology. Climatology; QC851-999; Antarctic; East Antarctica; Dronning Maud Land; East Antarctic Ice Sheet; Princess Elisabeth Base; Annals of Glaciology; Antarc*; Antarctica; Ice Sheet
• Online Access: https://doi.org/10.1017/aog.2019.26; https://doaj.org/article/054886c7f7614b76b010f4abcc6131bf

Over a year of seismic observations, ~5000 short duration icequakes were detected by a permanent broadband station installed at the Princess Elisabeth base, located ~180 km inland in eastern Dronning Maud Land, East-Antarctica. Icequake detection via seismic waveform pattern recognition indicates the presence of two dominating clusters of events, totalizing ~1500 icequakes. The corresponding icequake locations point towards two distinct zones of outcropping blue ice areas (BIAs) located respectively at 4 and 1 km from the seismic station, both on the leeward side of a nunatak protruding through the ice sheet. The temporal occurrence of these icequakes suggests a close genetic link with thermal contraction of ice caused by significant surface cooling controlled, in summer by variations in diurnal solar radiation and in winter by strong cooling during cold katabatic regimes. Further analysis demonstrates the dependence of these icequakes on the absolute surface temperature and on its temporal change. Besides providing information on the ice fracture mechanics and rheology, investigations of thermal icequakes may be regarded as a ground-based proxy for the monitoring of the thermal state of BIAs, and characterization of ice-sheet ablation zones.