April 2009 by Arthur Snoke (snoke@vt.edu)

This update to the July 2008 package has four changes:

1. A code change in subroutine finrng.f of program remodl solved an instability
that occurred when using the Sun f95 compiler.

2.  The test of the traveltime tables using program ttimes has been enhanced to
include a SAC script that plots predicted arrival times on observed waveforms. 
For the example used, it is found that one predicted phase based on the phase
set calculated by the iaspei-tau package is not the correct phase.  This is
discussed in a PDF file "phases.pdf" located in subdirectory
./iaspei-tau/tests/.

3.  To reach a wider audience about the history and availability of the
iaspei-tau package, I published a paper in Seismological Research Letters.  The
citation information is

Snoke, J.A. (2009), Traveltime Tables for iasp91 and ak135, Seismological
Research Letters, 80(2), 260-262.

4.  The build instructions have been modified slightly.  Now one enters
./build_package from the ./iaspei-tau directory.  This builds the executables
and makes the tables.  If one is not using gfortran, one must change FCOMP
before entering ./build_package.  The wording below has been modified to reflect
the updated instructions.
 
July 2008

This package contains the necessary software for building the traveltime tables
for velocity models iasp91 and ak135. The method is the one used in constructing
the ak135 traveltime tables (Kennett, Engdahl, and Buland, 1995), and a Fortran
compiler is required.  Also included is a program (ttimes) that can be used to
produce traveltimes, take-off angles, ray parameters, etc., for selected phases
and specified station-event geometry using iasp91 and/or ak135.  Sample output
files are included.  The ttimes source code (ttimes.f) can be used as a primer
for learning the syntax for reading the tables. 

The package is distributed in a gzipped tar file, iaspei-tau.tgz. On Unix, one
can both uncompress and expand this file with a single command:    

      tar -xzf iaspei-tau.tgz

or, if you are using an older version of tar that does not recognize -z,

      gzip -d -c iaspei-tau.tgz | tar -xf - 

This operation produces a directory ./iaspei-tau.  Instructions for building and
testing the tables are in the text file ./iaspei-tau/README_iaspei-tau.txt.