Details

Autor(en) / Beteiligte

• Ferrand, Thomas P.
• Hilairet, Nadège
• Incel, Sarah
• Deldicque, Damien
• Labrousse, Loïc
• Gasc, Julien
• Renner, Joerg
• Wang, Yanbin
• Green II, Harry W.
• Schubnel, Alexandre

Titel

Dehydration-driven stress transfer triggers intermediate-depth earthquakes

Ist Teil von

• Nature communications, 2017-05, Vol.8

Ort / Verlag

United States: Nature Publishing Group

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Intermediate-depth earthquakes (30–300 km) have been extensively documented within subducting oceanic slabs, but their mechanics remains enigmatic. Here in this paper we decipher the mechanism of these earthquakes by performing deformation experiments on dehydrating serpentinized peridotites (synthetic antigorite-olivine aggregates, minerals representative of subduction zones lithologies) at upper mantle conditions. At a pressure of 1.1 gigapascals, dehydration of deforming samples containing only 5 vol% of antigorite suffices to trigger acoustic emissions, a laboratory-scale analogue of earthquakes. At 3.5 gigapascals, acoustic emissions are recorded from samples with up to 50 vol% of antigorite. Experimentally produced faults, observed post-mortem, are sealed by fluid-bearing micro-pseudotachylytes. Microstructural observations demonstrate that antigorite dehydration triggered dynamic shear failure of the olivine load-bearing network. These laboratory analogues of intermediatedepth earthquakes demonstrate that little dehydration is required to trigger embrittlement. We propose an alternative model to dehydration-embrittlement in which dehydration-driven stress transfer, rather than fluid overpressure, causes embrittlement.