Physics-controlled thickness of shear zones caused by viscous heating: Implications for crustal shear localization

T. Duretz, S. M. Schmalholz, Y. Y. Podladchikov, D. A. Yuen

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

We evaluate the parameters that control the thickness of ductile shear zones that are generated by viscous heating. We employ two-dimensional thermomechanical numerical models to simulate shear zone development under compression. Results show that the shear zone thickness is essentially independent on the numerical resolution and the initial size of a weak inclusion that triggers shear localization. A simple scaling law is derived which predicts the thickness with six physical parameters: far-field stress and strain rate, thermal conductivity (both constant and temperature dependent), initial temperature, activation energy, and stress exponent. The scaling law is confirmed by numerical simulations for a wide range of parameters. For crustal deformation conditions typical temperature increase ranges between 50°C and 200°C, and the predicted thickness is between 1 km and 7 km. These thicknesses agree with natural crustal and lithospheric shear zones suggesting that shear heating is a process controlling crustal shear zone formation.

Original languageEnglish (US)
Pages (from-to)4904-4911
Number of pages8
JournalGeophysical Research Letters
Volume41
Issue number14
DOIs
StatePublished - Jul 28 2014

Keywords

  • lithosphere
  • scaling law
  • shear heating
  • shear localization
  • shear zone thickness

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