HYPODD_1.0

HypoDD is a Fortran77 computer program package for relocating earthquakes
with the double-difference algorithm of Waldhauser and Ellsworth (2000).
This is version 1.0 of hypoDD and should be referenced as Waldhauser
(2001).  The program has been extensively tested, but is made available
without warranty.  Users of the program are free to make modifications
to the programs to meet their particular needs, but are asked not to
distribute modified code to others.  Tell us about your improvements
and bug fixes, and we will add them to the code for everyone's benefit.

The complete program package is available via anonymous ftp from 
swave.wr.usgs.gov.  After login, cd pub/outgoing/HYPODD and get the
(binary) gzip-compressed tar file HYPODD_1.0.tar.gz .  This file can be
unpacked with the command

	gunzip -c HYPODD_1.0.tar.gz | tar xf -

		ORGANIZATION OF THE SOURCE CODE

The file HYPODD_1.0.tar.gz contains a directory subtree containing source
code and associated files implementing the "double-difference" earthquake-
location method of Waldhauser and Ellsworth (2000).  This README file
resides in the top-level directory.

CONTENTS OF THE TOP-LEVEL DIRECTORY

    README - This file.
    doc - Directory containing tutorial documentation.
    include - Directory containing source-code header files.
    src - Directory containing source code for commands, in separate
	subdirectories. 
    utils - Various utility programs/scripts.

Each directory contains its own README file explaining its contents
and usage.  For installation of hypoDD see the REAME files in the
src subtree.

                    TEST CASES AND EXAMPLES

Test and example cases are available via anonymous ftp from swave.wr.usgs.gov
in the separate tar file HYPODD_examples.tar.gz .  These files are unpacked
in the same manner as the source-code file, described above.  Each directory
contains a Readme file.

REFERENCES

Waldhauser, Felix, hypoDD -- A program to compute double-difference
hypocenter locations, U.S. Geological Survey Open-File Report 01-113, 2001.

Waldhauser, Felix, and William L. Ellsworth, A double-difference
earthquake location algorithm: Method and application to the northern
Hayward fault, California, BSSA, 90, 1353-1368, 2000.

BUG REPORTS, QUESTIONS, ENHANCEMENTS, ETC.

Please send questions, bug reports, news about how you have improved
the programs, etc. to julian@usgs.gov , with a copy to felix@andreas.wr.usgs.gov.