A fluid model for the shape of accretionary wedges

In this paper the accretionary wedges landward of most oceanic trenches are modelled assuming a Newtonian fluid rheology.It is shown that lubrication theory is applicable and that the addition of material to the wedges can be neglected in determining the shape of the wedges. The predicted shape of the wedges is in good agreement with bathymetric profiles across the Kurile, Ryukyu and Aleutian wedges. From the shape of the above wedges, it is deduced that accretionary sediments have viscosities between 10¹⁸ and 10¹⁹ poise.