Thermal structure and seismicity of subducting lithosphere

Emmerson, B. and McKenzie, D. P. (2007) Thermal structure and seismicity of subducting lithosphere. Physics of the Earth and Planetary Interiors, 163 (1-4). pp. 191-208. DOI 10.1016/j.pepi.2007.05.007

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Abstract

It has recently been suggested that the mechanical behaviour of the oceanic and continental uppermost mantle depends on temperature alone, and that there is no strong evidence for compositional effects. It seems in the majority of cases that, if uppermost mantle temperatures exceed 600 °C, any deformation that occurs does so in the absence of significant seismicity. This observation apparently applies irrespective of whether that mantle material underlies an ocean or a continent. This paper investigates whether the same behaviour exists for earthquakes occurring in descending lithospheric slabs, namely whether there is some limiting temperature above which deformation occurs without significant seismicity, and whether that limiting temperature is consistent with the behaviour seen in the uppermost mantle beneath oceans and continents. By re-examining the thermal structure in subducting slabs, accounting for the temperature dependence of the relevant physical parameters, teleseismically recorded seismicity is shown to be limited to material having potential temperatures less than not, vert, similar570–600 °C, or homologous temperatures less than not, vert, similar0.42. The exceptions to this pattern occur in the subhorizontally subducting regions of the Nazca Plate, in which temperatures are probably affected by the relatively cold overriding plate.

Item Type: Article
Uncontrolled Keywords: 2007 AREP IA52 IA55 2007 P
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Physics of the Earth and Planetary Interiors
Volume: 163
Page Range: pp. 191-208
Identification Number: 10.1016/j.pepi.2007.05.007
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:02
Last Modified: 23 Jul 2013 10:06
URI: http://eprints.esc.cam.ac.uk/id/eprint/272

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