The Impact of a Very Weak and Thin Upper Asthenosphere on Subduction Motions

R. Carluccio, B. Kaus, F. A. Capitanio, L. N. Moresi

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Abstract

Recent geophysical observations report the presence of a very weak and thin upper asthenosphere underneath subducting oceanic plates at convergent margins. Along these margins, trench migrations are significantly slower than plate convergence rates. We use numerical models to assess the role of a weak upper asthenospheric layer on plate and trench motions. We show that the presence of this layer alone can enhance an advancing trend for the motion of the plate and hamper trench retreat. This mechanism provides a novel and alternative explanation for the slow rates of trench migration and fast-moving plates observed globally at natural subduction zones.

Original languageEnglish
Pages (from-to)11893-11905
Number of pages13
JournalGeophysical Research Letters
Volume46
Issue number21
DOIs
Publication statusPublished - 16 Nov 2019

Keywords

  • asthenosphere
  • numerical modeling
  • oceanic lithosphere
  • plate motion
  • subduction zone processes

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