SMU Geophysics Extended-Depth Seismic Traveltime Tables by
Ileana M. Tibulea, David P. Anderson, Eugene Herrin
Southern Methodist University

This directory contains the extended p-wave seismic travel time table created by Dr. Ileana Tibuleac for the SMU Linear Event Recognizer. It is calculated to depths of 2880 kilometers, the core-mantle boundary, in 10 kilometer steps, and to distances of 98 angular degrees, in 1 degree steps. This table was generated by raytracing the standard earth model (IASPI) and calibrating with published data to 799 kilometers, and with signals reflected from the core/mantle interface.

The data is in the form of a C "struct" as an array of 99 x 289 floats. Subroutines are provided for table lookup and linear interpolation of the table entries in the file "ttime.c" A command line interface is provided in the file "tt.c" which takes two arguments, depth in km and angular distance in degrees, and returns a travel time in seconds. This code was compiled with the gnu gcc compiler.

Here is a sample tt command and its output:

$ tt 1445 45.6
1450.00 km 45.60 deg 411.07 sec

For depth/distance combinations that are shadowed by the earth's core, the routine returns "no_data" as the travel time.

The directory is available as a Unix tar archive, ttime_src.tar (410k) and also as a gzip'd Unix tar archive, ttime_src.tar.gz (146k).
The files are also available separately (below) as a set of regular ASCII files:

README (1001)
makefile (295)
table2.h (398754)
tt.c (2249)
ttime.c (2968)

11 Dec 02
dpa

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