Subducted seafloor relief stops rupture in South American great earthquakes: Implications for rupture behaviour in the 2010 Maule, Chile earthquake

Sparkes, Robert and Tilmann, Frederik and Hovius, Niels and Hillier, John (2010) Subducted seafloor relief stops rupture in South American great earthquakes: Implications for rupture behaviour in the 2010 Maule, Chile earthquake. Earth and Planetary Science Letters, 298 (1-2). pp. 89-94. ISSN 0012821X DOI 10.1016/j.epsl.2010.07.029

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Official URL: http://dx.doi.org/10.1016/j.epsl.2010.07.029

Abstract

Great subduction earthquakes cause destructive surface deformation and ground shaking over hundreds of kilometres. Their rupture length is limited by the characteristic strength of the subduction plate interface, and by lateral variations in its mechanical properties. It has been proposed that subduction of topographic features such as ridges and seamounts can affect these properties and stop rupture propagation, but the required relief and physical mechanisms of topographic rupture limitation are not well understood. Here, we show that the rupture limits of thirteen historic great earthquakes along the South America–Nazca plate margin are strongly correlated with subducted topography with relief > 1000 m, including the Juan Fernandez Ridge. The northern limit of rupture in the Mw 8.8 Maule, Chile earthquake of 27 February 2010 is located where this ridge subducts. Analysis of intermediate-magnitude earthquakes shows that in most places, the subduction of high seafloor relief creates weak, aseismic zones at the plate interface, which prevent rupture propagation, but that the Juan Fernandez Ridge is associated with a locally strong plate interface. The maximum rupture length, and thus magnitude, of great subduction earthquakes is therefore determined by the size and lateral spacing of topographic features where they are present on the subducting plate.

Item Type: Article
Uncontrolled Keywords: 2010AREP; IA61, Part III
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Earth and Planetary Science Letters
Volume: 298
Page Range: pp. 89-94
Identification Number: 10.1016/j.epsl.2010.07.029
Depositing User: Sarah Humbert
Date Deposited: 05 Oct 2010 07:32
Last Modified: 23 Jul 2013 10:00
URI: http://eprints.esc.cam.ac.uk/id/eprint/1944

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