Relationship of geodetic velocities to velocities in the mantle

Abstract

We examine the relationship of the velocities at the surface (i.e., geodetic velocities) to the velocities in the upper-most mantle throughout a seismic cycle. We model the rheology of the lower crust and mantle as linear viscoelastic, and vary the relative viscosities between the lower crust and mantle, as well as the distribution of viscosities and secular velocities in the mantle. We find that the geodetic velocities are related to the transient velocities at depth; the strength of the relationship decreases as the contrast between the lower crust and mantle viscosity increases. In these models we find that the geodetic velocities are not related to the secular velocities at depth. Copyright 2004 by the American Geophysical Union.