HYPODD Version 1.3 
==================

by Felix Waldhauser (felixw@ldeo.columbia.edu)

Version 1.0 - 03/2001 - FW
Version 1.1 - 10/2004 - FW
Version 1.2 - 07/2010 - FW
Version 1.3 - 08/2010 - FW  (same as v1.2, but compiles with gfortran)

HypoDD is a Fortran77 computer program package for relocating earthquakes
with the double-difference algorithm of Waldhauser and Ellsworth (2000).
This is version 1.3 of hypoDD and should be referenced as Waldhauser
(2001). Version 1.3 has the errors listed in the buglists of previous 
versions fixed.

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 
ftp.ldeo.columbia.edu.  After login, cd archive/felix/HYPODD and get the
(binary) gzip-compressed tar files
   HYPODD_1.3.tar.gz   (source codes and user guide; 1.4MB)
   HYPODD_examples.tar.gz   (small and medium size example data sets; 2.4MB)
   HYPODD_moreExamples.tar.gz   (3 large example data sets; 78.9MB)
   README  (how to get started...)
   BUGLIST_1.3  (continously updated bug list for HYPODD version 1.3)

Alternatively, these files can be downloaded from 
   http://www.ldeo.columbia.edu/~felixw/hypoDD.html

The files can be unpacked with the command
   gunzip -c HYPODD_1.3.tar.gz | tar xf -


			ORGANIZATION OF THE SOURCE CODE

The file HYPODD_1.3.tar.gz contains a directory subtree containing source
code and associated files implementing the "double-difference" earthquake-
location method. 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 README files in the
src subtree.


			TEST CASES AND EXAMPLES

Test and example cases are included in the files HYPODD_examples.tar.gz (small 
and medium size example data sets; 2.4MB) and HYPODD_moreExamples.tar.gz  (3 
large example data sets; 78.9MB). These files are unpacked in the same manner 
as the source-code file, described above.  Each directory contains a Readme 
file.


			IMPORTANT NOTE

If the programs abort with 'Killed' when executed, then there is most
likely not enough memory available on the computer on which the
programs are started.  Switch to a larger computer or edit hypoDD.inc
and/or ph2dt.inc in the directory include/ to adjust array dimensions
according to the size of the problem to be solved or available computer
memory.

			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 felixw@ldeo.columbia.edu.