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GPS network monitors the Western Alp's deformation over a five-year period: 1993-1998 / Christophe Vigny in Journal of geodesy, vol 76 n° 2 (February 2002)  

Public [article]  inJournal of geodesy > vol 76 n° 2 (February 2002) . - pp 63 - 76 Titre : GPS network monitors the Western Alp's deformation over a five-year period: 1993-1998 Type de document : Article/Communication Auteurs : Christophe Vigny, Auteur ; J. Chery, Auteur ; Thierry Duquesnoy , Auteur ; et al., Auteur Année de publication : 2002 Article en page(s) : pp 63 - 76 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Alpes occidentales [Termes IGN] déformation de la croute terrestre [Termes IGN] montagne [Termes IGN] positionnement par GPS [Termes IGN] surveillance géologique [Termes IGN] tectonique [Termes IGN] triangulation (topologie) Résumé : (Auteur) The Western Alps are among the best studied collisional belts with both detailed structural mapping and also crustal geophysical investigations such as the ECORS and EGT seismic profile. By contrast, the present-day kinematics of the belt is still largely unknown due to small relative motions and the insufficient accuracy of the triangulation data. As a consequence, several tectonic problems still remain to be Occidental Alps, the repartition of the deformation between the Alpine tectonic units, and the relation between deformation and rotation across the Alpine arc. In order to address these problems, the GPS ALPES group, made up of French, Swiss and Italian research organizations, has achieved the first large-scale GPS surveyed in 1993 and 1998 with a minimum observation of 3 days at each site. GPS data processing has been done by three independent teams using different soft-ware. The different solutions have horizontal repeat-abilities (N-E) of 4-7 min in 1993 and 2-3 mm in 1998 and compare at the 3-5-mm level in position and 2-mm/yr level in velocity. A comparison of 1993 and 1998 coordinates shows that residual velocities of the GPS marks are generally smaller than 2 mm/yr, precluding a detailed tectonic interpretation of the differential motions. However, these data seem to suggest that the N-S compression of the Western Alps is quite mild (less than 2 mm/yr) compared to the global convergence between the African and Eurasian plate (6 mm/yr). This implies that the shortening must be accomodated elsewhere by the deformation of the Maghrebids and/ or by rotations of Mediterranean microplates. Also, EW velocity components analysis supports the idea that E-W extension exists, as already suggested by recent structural and seismotectonic data interpretation Numéro de notice : A2002-018 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-001-0231-8 En ligne : https://doi.org/10.1007/s00190-001-0231-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21935 [article]

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