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End of subduction in northern Apennines confirmed by observations of quasi‐Love waves from the great 2004 Sumatra‐Andaman earthquake
Author(s) -
Levin V.,
Park J.,
Lucente F. P.,
Margheriti L.,
Pondrelli S.
Publication year - 2007
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 - 10.1029/2006gl028860
Subject(s) - geology , subduction , seismology , lithosphere , mantle (geology) , rayleigh wave , slab , geophysics , love wave , surface wave , tectonics , wave propagation , longitudinal wave , mechanical wave , physics , quantum mechanics , computer science , telecommunications
Surface waves from the great Sumatra‐Andaman earthquakes of 2004 and 2005 that cross Italy south of ∼44°N display Love‐to‐Rayleigh scattered waves (quasi‐Love phases) diagnostic of sharp lateral gradients in the anisotropic properties of Earth's upper mantle. Surface waves that traverse Italy further north lack this distinctive phase, documenting a change in the upper mantle fabric that is corroborated by a shift in the fast polarization of shear wave birefringence. These observations suggest that orogen‐parallel asthenospheric extension behind the retreating Apennines slab has limited geographical expression. We hypothesize that subduction rollback currently terminates at 44°N, while the upper mantle flow pattern further to the north has been recently rearranged.