Stress orientations in subduction zones and the strength of subduction megathrust faults

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Abstract

Subduction zone megathrust faults produce most of the world’s largest earthquakes. Although the physical properties of these faults are difficult to observe directly, their frictional strength can be estimated indirectly by constraining the orientations of the stresses that act on them. A global investigation of stress orientations in subduction zones finds that the maximum compressive stress axis plunges systematically trenchward, consistently making an angle of 45° to 60° with respect to the subduction megathrust fault. These angles indicate that the megathrust fault is not substantially weaker than its surroundings. Together with several other lines of evidence, this implies that subduction zone megathrusts are weak faults in a low-stress environment. The deforming outer accretionary wedge may decouple the stress state along the megathrust from the constraints of the free surface.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Stress orientations in subduction zones and the strength of subduction megathrust faults
Series title Science
DOI 10.1126/science.aac5625
Volume 349
Issue 6253
Year Published 2015
Language English
Publisher American Association for the Advancement of Science
Publisher location New York, NY
Description 4 p.
First page 1213
Last page 1216
Online Only (Y/N) N
Additional Online Files (Y/N) N