P-velocity, radially aniostropic, 3-dimensional mantle model 8, after Boschi & Dziewonski (JGR, 2000). This model is obtained from P, PcP, PKP data (based on ISC bullettin after appropriate corrections), with the assumption that the outer core be spherically symmetric. Of all the models published by Boschi & Dziewonski (JGR, 2000), we consider this one to be the most realistic. Approximately equal area block model (5 degrees X 5 degrees X 193.3 km). It includes two images of the mantle, one for horizontal P-velocity (files h*.d) the other for vertical P-velocity (files v*.d); it also includes an image of the core-mantle boundary topography (file cmb.d). The mantle files are defined as for model BDP98: the layers are given in the files vlaye_01.d through vlaye_15.d, and hlaye_01.d through hlaye.15.d in the following format (example): 1.25403E-02 0. 85.0000 0. 90.0000 90.0000 90.0000 90.0000 85.0000 -0.301233 90.0000 85.0000 90.0000 90.0000 180.000 90.0000 180.000 85.0000 -0.391459 180.000 85.0000 180.000 90.0000 270.000 90.0000 270.000 85.0000 the single numbers are the value of the PERCENT velocity perturbation relative to PREM within each block; the following four pairs of numbers are longitude and latitude of the four vertices of the corresponding block... and so on... I believe that the best way to plot this file is to use gmt. First you need to write a program to turn each file into something like: > -G165/243/172 0. 85.0000 0. 90.0000 90.0000 90.0000 90.0000 85.0000 > -G255/184/101 90.0000 85.0000 90.0000 90.0000 180.000 90.0000 180.000 85.0000 > -G255/162/071 180.000 85.0000 180.000 90.0000 270.000 90.0000 270.000 85.0000 where the three integers after -G, separated by /, define the color corresponding to the velocity perturbation in the block (and then the block-vertices coordinates are just the same), based on a colorscale of your choice. Assuming that you called this new file image, you can use (more or less) the commands psxy image -JH180/6 -Bg45/g45 -R0/360/-90/90 -K -M >! fig.ps pscoast -R0/360/-90/90 -O -JH180 -W1 -Dc -A5000 >> velocity.ps to obtain a figure with that layer of the model (and the coastline). For comparison, the postcripts files vh.ps (horizontal P-velocity) and vv.ps (vertical P-velocity) are given, which include the lateral velocity perturbations for all the layers in our model, in order of increasing depth (1--15) from left to right and top to bottom. The color scale saturates at 1%. The CMB file cmb.d is given in the same format and can be plotted in the same fashion. The CMB topography anomalies are defined as elevation with respect to the constant CMB radius of PREM; in practice, a positive topography anomaly corresponds to elevated CMB, while a negative anomaly corresponds to depressed CMB. Compare with the figure cmb.ps (where the average cmb perturbation was set to zero); the color scale, there, saturates at 10km. Lapo Boschi, Cambridge, July 25, 1999. boschi@seismology.harvard.edu