********** MODEL DESCRIPTION **********

The model saw24b16 is a VSH model parametrized laterally in spherical 
harmonics up to degree 24 (Edmonds normalization) and radially in 16 
unevenly spaced splines (my own normalization but the code is in spl.c 
in the tar file).

**********DATA **********

The model was derived with handpicked waveforms of SH body waves (S,SS,S3,S4,ScS,ScS2,ScS3,Sdiff and corresponding depth phases: sS, etc...), 
1st & 2nd orbit Love waves, 1st & 2nd orbit higher mode waveforms.

********** ALTERNATIVE FORMAT **********

The model pregridded (2x2 degrees) at 30 mantle depths can be downloaded
anonymously from the ftp site:
quake.geo.berkeley.edu
cd outgoing/pepe/
saw24b16.grid.2x2.tar.gz (2.3 Mb)

If this format is inadequate for your application, the following 
describes how to extract model values at an arbitrary depth. 

********** MODEL FILE DESCRIPTION **********

The model coefficients are in the file saw24b16.A1d

There are 2 header lines :
24 16 2 seafl moho -> max spherical harmonic degree / # of radial b-splines / # of discontinuities / name of disc.
3479.958 3600.000 (...) location of the b-spline knots.

Follow 18 (16 splines + bathymetry/topography + moho) blocks of 625 (25*25) spherical harmonic coefficients. 

********** COMPILATION **********

Uncompress & extract the code from the tar file:
gunzip saw24b16.grid.tar.gz
tar xvf saw24b16.grid.tar

To compile :
make -f A1dgrid.mk

This will store the executable in the DUMP/ directory
The code was tested on SOLARIS and Linux. 

********** RUNNING THE CODE **********

A1dgrid reads the coefficients from the model file saw24b16.A1d
and outputs model values (in % perturbation from PREM) on an grid 
(default 2x2 degrees)

To plot a lateral section of the model, run the shell A1dgrid

(smin & smax are the minimum and maximum spherical harmonic degrees
to be plotted)

********** SAMPLE RUN **********

Following is a sample run that generates a 2x2 degree grid (default) 
of saw24b16.A1d at 250 km depth (degrees 1 to 24). Output file is stored as 
'saw24b16.250km.dat'

pepe@andy:(245)% ./A1dgrid

File name: saw24b16.A1d
 Depth range: [  25 2891] km;  Discontinuities: seafl moho
 Specify a depth, or 's' 'm'  for discontinuity, or 'q' to quit:250

Max degree of model is 24
smin & smax of grid :1 24

Type 'a' to grid  all degrees
     'e' to grid even degrees only
 or  'o' to grid  odd degrees only  :a
Enter name of output file > saw24b16.250km.dat
 Specify a depth, or 'm'  for discontinuity, or 'q' to quit:q

********** PREPRINTS **********

A preprint of the manuscript submitted to GJI (presently in revision 5/2000) 
can be found on the ftp site in the same directory as above: 
saw24b16.gji.ps.gz (1.3 Mb)

********** SAW24B16 ON THE WEB **********

Further information on saw24b16 can be found at the URL:
http://www.seismo.berkeley.edu/~pepe/saw24b16.html



For all enquiries, please contact Charles Megnin
pepe@seismo.berkeley.edu