README FILES FOR SCRIPPS MODELS S16B30 and P16B30:

s16b30 and p16b30 are 3d models of shear and compressional
velocities of the Earth's mantle. Both models are parameterized
in terms of spherical harmonics laterally (up to l=16) and
B-splines radially (30).
The models are delta v/v (if you want percent, just multiply
by 100).
We used fully normalized spherical harmonics (Edmonds, 1960)
to derive the models.
s16b30 is described in Masters et al. (1996). The spherical
averages of the models have been taken out.

There are two fortran source codes (which have to be
compiled once you ftp-ed them on your machine).

Givelm gives the spherical harmonic expansion of the model
at a chosen depth. Remember to chosen lmax to be smaller
or equal to 16 (higher number don't make sense). The output
file is outlm.

Modeval calculates a map (5x5 degrees) at a chosen depth.
The output file is outmap. There are two sample maps at
530 and 2750km depth. 

There are two postscript files (s16b30.ps, p16b30.ps) which
show a number of maps at given depths. Remember to chosen
the binary option during ftp. After an ftp, the maps need
to be decompressed (e.g. uncompress s16b30).
We also provide Figure 18 of Masters et. al. (1996). This
figure shows cross sections through the mantle along given
great circles (as marked in the middle). The perturbations
are delta v/v in percent. 

References:

Edmonds, A.R., Angular Momentum in Quantum Mechanics,  
Princeton Univ. Press, Princeton, N.J., 1960.

Masters, G., S. Johnson, G. Laske and H. Bolton, A shear-
velocity model of the mantle, Phil. Trans. R. Soc. London A,
354, 1385-1411, 1996.