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

Abstract

Faults well oriented for failure A deck of cards will remain motionless while pressed on from above, but easily separates when sheared. Similarly, the ease by which geological faults rupture depends on the geometry of the fault relative to the size and direction of stress. Hardebeck finds that faults are well oriented for failure in subduction zones worldwide, suggesting a low-stress environment (see the Perspective by Bürgmann). Subduction zone faults unleash powerful earthquakes. These estimates on the state of stress constrain potential generation mechanisms of destructive subduction zone earthquakes. Science , this issue p. 1213 ; see also p. 1162