Elastic-plastic bending of the lithosphere incorporating rock deformation data, with application to the structure of the Hawaiian archipelago

An elastic-plastic lithosphere bending model incorporating rock deformation data has been developed for computation of flexure profiles at mid-ocean island chains and at the trenches near the plate boundaries. Flexure of the plate is computed by finite-element numerical solution of Von Kármán's equation for large deflection of plates with a nonlinear material behavior. The elastic part of the constitutive relation is derived from seismology (moduli = 90% of the seismic values) while the strain rate-dependent plastic part is derived from dunite deformation data extrapolated to the appropriate geologic loading rates. As an illustration, the amplitude and the wavelength of the Hawaiian Arch, the vertical displacement of the Moho under the Hawaiian Archipelago, and the free-air gravity anomalies are fitted to within observation accuracy by the present lithosphere flexure model.