Isostasy and the ambient state of stress in the oceanic lithosphere

It is proposed that the ambient state of isostatic deviatoric stress in the ocean lithosphere is the minimum necessary for the support of the density and topographic anomalies associated with the elevation of the mid-ocean ridges. The principal evidence for this hypothesis is that it is in agreement with the observed oceanic intraplate earthquake mechanisms. The main deviatoric stresses are compressive perpendicular to the axis of the mid-ocean ridge, zero parallel to the ridge, and tensile vertically. At any given distance from the ridge the stress is maximum at the seafloor; it decreases with depth at about the same rate as the cooling of the lithosphere, so that the entire thermal boundary layer acts as a support to the global square root of age topography of the oceans.