Bending as a mechanism for triggering off-axis volcanism on the East Pacific Rise

Abstract

We propose that bending stresses play a key role in triggering volcanism on the flanks of the East Pacific Rise by simultaneously opening tensile cracks near the surface and increasing the pore pressure of melt bodies trapped in the lower crust. In addition, crack-tip stress intensities remain high during tensile opening, such that bending cracks propagate downward efficiently and thus have the potential to tap overpressured melt bodies trapped in the lower crust. We find that bending increases the vulnerability of the lithosphere to magmatic penetration out to distances of ∼20 km from the rise axis, corresponding to the region of abyssal hill formation and isolated seamount generation.