Ocean trench topography

Dynamically Supported Trench Topography

A viscous flow model of a subduction zone is used to calculate the near-trench deformation and topography of the overriding plate in response to tectonic and buoyancy forces. The tectonic force, which is associated with global plate motion, arises from subduction of a cold oceanic lithosphere that shears the overriding lithosphere along the contact between the two plates. The buoyancy force ari...

Ocean Surface Topography

Definition The deviation of the height of the ocean surface from the geoid is known as the ocean surface topography. The geoid is a surface on which the Earth’s gravity field is uniform. The ocean surface topography is caused by ocean waves, tides, currents, and the loading of atmospheric pressure. The main application of ocean surface topography is for the determination of large-scale ocean ci...

Controls on trench topography from dynamic models of subducted slabs

A finite element method with constrained elements and Lagrange multipliers is used to study tectonic faults in a viscous medium. A fault, representing the interface between overriding and subducting plates, has been incorporated into a viscous flow model of a subduction zone in which both thermal buoyancy and the buoyancy associated with the phase change from olivine to spinel are included. The...

Variability of Southern Ocean Jets near Topography

The interaction of jets with topography in the Southern Ocean is investigated using 19 years of altimetry data. In particular, the ‘‘jet jumping’’ mode of variability, by which two or more jets passing close to the same topographic feature show strongly anticorrelated strengthening and weakening, is studied. Three regional case studies are described—the Southeast Indian Ridge south of Tasmania,...

Varying mechanical coupling along the Andean margin: Implications for trench curvature, shortening and topography