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Bimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf / Denis Lombardi in Geophysical journal international, vol 206 n° 2 (August 2016)  

Public [article]  inGeophysical journal international > vol 206 n° 2 (August 2016) . - pp 1375 - 1381 Titre : Bimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf Type de document : Article/Communication Auteurs : Denis Lombardi, Auteur ; Lionel Benoit , Auteur ; Thierry Camelbeeck, Auteur ; Olivier Martin , Auteur ; Christophe Meynard , Auteur ; Christian Thom , Auteur Année de publication : 2016 Article en page(s) : pp 1375 - 1381 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Antarctique [Termes IGN] calotte glaciaire [Termes IGN] coordonnées GPS [Termes IGN] déformation de la croute terrestre [Termes IGN] marée terrestre [Termes IGN] séisme Résumé : (auteur) In Antarctica, locally grounded ice, such as ice rises bordering floating ice shelves, plays a major role in the ice mass balance as it stabilizes the ice sheet flow from the hinterland. When in direct contact with the ocean, the ice rise buttressing effect may be altered in response of changing ocean forcing. To investigate this vulnerable zone, four sites near the boundary of an ice shelf with an ice rise promontory in Dronning Maud Land, East-Antarctica were monitored for a month in early 2014 with new instruments that include both seismic and GPS sensors. Our study indicated that this transition zone experiences periodic seismic activity resulting from surface crevassing during oceanic tide-induced flexure of the ice shelf. The most significant finding is the observation of apparent fortnightly tide-modulated low-frequency, long-duration seismic events at the seaward front of the ice rise promontory. A basal origin of these events is postulated with the ocean water surge at each new spring tide triggering basal crevassing or basal slip on a local bedrock asperity. Detection and monitoring of such seismicity may help identifying ice rise zones vulnerable to intensified ocean forcing. Numéro de notice : A2016--191 Affiliation des auteurs : LASTIG LOEMI+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggw214 Date de publication en ligne : 05/06/2016 En ligne : https://doi.org/10.1093/gji/ggw214 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91841 [article]