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

September 11, 2015

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 a 45°-60° angle 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.

Citation Information

Publication Year 2015
Title Stress orientations in subduction zones and the strength of subduction megathrust faults
DOI 10.1126/science.aac5625
Authors Jeanne L. Hardebeck
Publication Type Article
Publication Subtype Journal Article
Series Title Science
Series Number
Index ID 70157191
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center

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