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Icelandic rhythmics: Annual modulation of land elevation and plate spreading by snow load
Author(s) -
Grapenthin Ronni,
Sigmundsson Freysteinn,
Geirsson Halldór,
Árnadóttir Thóra,
Pinel Virginie
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028081
Subject(s) - geology , snow , volcano , displacement (psychology) , elevation (ballistics) , ice caps , geodesy , climatology , atmospheric sciences , seismology , geomorphology , geometry , mathematics , psychology , glacier , psychotherapist
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.