Icelandic rhythmics: Annual modulation of land elevation and plate spreading by snow load

• Published in: Geophysical Research Letters
• Main Authors: Grapenthin, Ronni, Sigmundsson, F., Geirsson, H., Árnadóttir, Thóra, Pinel, V.
• Other Authors: Nordic Volcanological Center, Institute of Earth Sciences, Institute of Earth Sciences University of Iceland, University of Iceland Reykjavik -University of Iceland Reykjavik, Icelandic Meteorological Office, celandic Meteorological Office, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: crustal deformation; Green's functions; continuous GPS; [SDU]Sciences of the Universe [physics]; Ice cap; Iceland; Vatnajökull
• Online Access: https://insu.hal.science/insu-00267008; https://insu.hal.science/insu-00267008/document; https://insu.hal.science/insu-00267008/file/ark%20_67375_WNG-3LSCM7B5-S.pdf; https://doi.org/10.1029/2006GL028081

International audience We find strong correlation between seasonal variation in CGPS time series and predicted response to annual snow load in Iceland. The load is modeled using Green's functions for an elastic halfspace and a simple sinusoidal load history on Iceland's four largest ice caps. We derive E = 40 ± 15 GPa as a minimum value for the effective Young's modulus in Iceland, increasing with distance from the Eastern Volcanic Zone. We calculate the elastic response over all of Iceland to maximum snow load at the ice caps using E = 40 GPa. Predicted annual vertical displacements are largest under the Vatnajökull ice cap with a peak-to-peak seasonal displacement of ∼37 mm. CGPS stations closest to the ice cap experience a peak-to-peak seasonal displacement of ∼16 mm, consistent with our model. East and north of Vatnajökull we find the maximum of annual horizontal displacements of ∼6 mm resulting in apparent modulation of plate spreading rates in this area.