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

• Published in: Annals of Glaciology
• Main Authors: Lombardi, Denis, Gorodetskaya, Irina, Barruol, Guilhem, Camelbeeck, Thierry
• Other Authors: Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Centre for Environmental and Marine Studies (CESAM), Department of Environment and Planning, University of Aveiro, Royal Observatory of Belgium Brussels (ROB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: seismology; Antarctic glaciology; blue ice; ice rheology; ice temperature; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Antarctic; Dronning Maud Land; East Antarctic Ice Sheet; East Antarctica; Princess Elisabeth Base; Annals of Glaciology; Antarc*; Antarctica; Ice Sheet
• Online Access: https://hal.archives-ouvertes.fr/hal-02289922; https://hal.archives-ouvertes.fr/hal-02289922/document; https://hal.archives-ouvertes.fr/hal-02289922/file/Lombardi_thermally_induced_icequakes_Ann_Glacio_2019.pdf; https://doi.org/10.1017/aog.2019.26

International audience 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.