Subdirectories ?mean_wus hold averages (dv.*.grd) and standard
deviations (std.*.grd) from "stacking" western US tomograhic models
SH11, DNA09, and NWUS after up-scaling to the depth-averaged RMS of
SH11.

Models are given bottom up, at depths as specified in the depths.dat
files. 

From 

Becker, T. W. (2011): On recent seismic tomography for the western
United States. In preparation.



Original references:

SH11: 

Schmandt, B., and E. Humphreys (2010), Complex subduction and
small-scale convection revealed by body-wave tomography of the western
United States upper mantle, Earth Planet. Sci. Lett., 297, 435–445.

DNA09:

Obrebski, M., R. M. Allen, M. Xue, and S.-H. Hung (2010), Slab-plume
interac- tion beneath the Pacific Northwest, Geophys. Res. Lett., 37
(L14305), doi:10.1029/ 2010GL043489.

NWUS: 

James, D. E., M. J. Fouch, R. W. Carlson, and J. B. Roth (2011), Slab
fragmentation, edge flow and the origin of the Yellowstone hotspot
track, Earth Planet. Sci. Lett., 311, 124–135.

