Preprints
https://doi.org/10.31223/X5B31X
https://doi.org/10.31223/X5B31X
 
22 Aug 2022
22 Aug 2022
Status: this preprint is open for discussion.

The effect of temperature-dependent material properties on simple thermal models of subduction zones

Iris van Zelst1,2, Cedric Thieulot3, and Timothy J. Craig1 Iris van Zelst et al.
  • 1Institute for Geophysics and Tectonics, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
  • 2Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
  • 3Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands

Abstract. To a large extent, the thermal structure of a subduction zone determines where seismicity occurs through controls on the transition from brittle to ductile deformation and the depth of dehydration reactions. Thermal models of subduction zones can help understand the distribution of seismicity by accurately modelling the thermal structure of the subduction zone. Here, we assess a common simplification in thermal models of subduction zones, i.e., constant values for the thermal parameters. We use temperature-dependent parameterisations, constrained by lab data, for the thermal conductivity, heat capacity, and density, to systematically test their effect on the resulting thermal structure of the slab. To isolate this effect, we use the well-constrained, thoroughly studied, and highly simplified model setup of the subduction community benchmark by Van Keken et al. (2008) in a 2D finite element code. To ensure a self-consistent and realistic initial temperature-profile for the slab, we implement a 1D plate model for cooling of the oceanic lithosphere with an age of 50 Myr in favour of the previously used half-space model. Our results show that using temperature-dependent thermal parameters in thermal models of subduction zones results in a slightly cooler plate with e.g., the 600 °C isotherm reaching almost 30 km deeper. From this, we infer that these models would predict a larger estimated seismogenic zone and a larger depth at which dehydration reactions responsible for intermediate-depth seismicity occur. We therefore recommend that thermo(-mechanical) models of subduction zones take temperature-dependent thermal parameters into account, especially when inferences on seismicity are made.

Iris van Zelst et al.

Status: open (until 27 Oct 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Iris van Zelst et al.

Iris van Zelst et al.

Viewed

The metrics are limited to the final revised paper since the preprint was posted outside of Copernicus Publications.

Total article views: 60 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
60 0 0 60 3 0
  • HTML: 60
  • PDF: 0
  • XML: 0
  • Total: 60
  • BibTeX: 3
  • EndNote: 0
Views and downloads (calculated since 22 Aug 2022)
Cumulative views and downloads (calculated since 22 Aug 2022)

Viewed (geographical distribution)

The metrics are limited to the final revised paper since the preprint was posted outside of Copernicus Publications.

Total article views: 54 (including HTML, PDF, and XML) Thereof 54 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 28 Sep 2022
Download
Short summary
A common simplification in subduction zone models is the use of constant thermal parameters, while experiments have shown that they vary with temperature. We test various formulations of T-dependent thermal parameters and show that they change the thermal structure of the subducting slab. We therefore recommend that modelling studies of the thermal structure of subduction zones take the T-dependence of thermal parameters into account, especially when they aim to provide insight into seismicity.