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Dislocation interactions in olivine control postseismic creep of the upper mantle

Published version
Peer-reviewed

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Authors

Hansen, Lars N. 
Wilkinson, Angus J.  ORCID logo  https://orcid.org/0000-0002-8801-4102
Lebensohn, Ricardo A.  ORCID logo  https://orcid.org/0000-0002-3152-9105

Abstract

Abstract: Changes in stress applied to mantle rocks, such as those imposed by earthquakes, commonly induce a period of transient creep, which is often modelled based on stress transfer among slip systems due to grain interactions. However, recent experiments have demonstrated that the accumulation of stresses among dislocations is the dominant cause of strain hardening in olivine at temperatures ≤600 °C, raising the question of whether the same process contributes to transient creep at higher temperatures. Here, we demonstrate that olivine samples deformed at 25 °C or 1150–1250 °C both preserve stress heterogeneities of ~1 GPa that are imparted by dislocations and have correlation lengths of ~1 μm. The similar stress distributions formed at these different temperatures indicate that accumulation of stresses among dislocations also provides a contribution to transient creep at high temperatures. The results motivate a new generation of models that capture these intragranular processes and may refine predictions of evolving mantle viscosity over the earthquake cycle.

Description

Keywords

Article, /704/4111, /704/2151/2809, /704/2151/508, /147, /147/135, article

Journal Title

Nature Communications

Conference Name

Journal ISSN

2041-1723

Volume Title

12

Publisher

Nature Publishing Group UK
Sponsorship
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (Netherlands Organisation for Scientific Research) (ALWGO.2018.038)
RCUK | Natural Environment Research Council (NERC) (NE/M000966/1)