Related Experiment Video
Updated: Jul 7, 2026

Small Volume (1-3L) Filtration of Coastal Seawater Samples
Published on: June 19, 2009
The mantle flow field beneath western North America
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA. silver@dtm.ciw.edu
Abstract:
Although motions at the surface of tectonic plates are well determined, the accompanying horizontal mantle flow is not. We have combined observations of surface deformation and upper mantle seismic anisotropy to estimate this flow field for western North America. We find that the mantle velocity is 5.5 +/- 1.5 centimeters per year due east in a hot spot reference frame, nearly opposite to the direction of North American plate motion (west-southwest). The flow is only weakly coupled to the motion of the surface plate, producing a small drag force. This flow field is probably due to heterogeneity in mantle density associated with the former Farallon oceanic plate beneath North America.
Related Concept Videos
Energy Line and Hydraulic Gradient Line
General External Flow Characteristics
Uniform Depth Channel Flow
Gradually Varying Flow
Rapidly Varying Flow
Underflow Gates

