SAC (Seismic Analysis Code) is a general purpose interactive program designed for the study of sequential signals, especially timeseries data. Emphasis has been placed on analysis tools used by research seismologists in the detailed study of seismic events. Analysis capabilities include general arithmetic operations, Fourier transforms, three spectral estimation techniques, IIR and FIR filtering, signal stacking, decimation, interpolation, correlation, and seismic phase picking. SAC also contains an extensive graphics capability.
Version 101.4 of SAC is now available for download from http://ds.iris.edu/software/sac/.
For a summary of the changes between this version and 101.3b (released August 2009), one can view the HISTORY file. That file, as well as the more detailed CHANGES file, can also be accessed from the IRIS software/sac page.
As before, there are binary distributions for Sun Solaris, Linux (32 bit and 64 bit) and Mac OS X. There are now two binary distributions for the Mac: the 32-bit “fat binary” version as in previous releases that can run on all OS levels, and a 64-bit version for Mac OS 10.6. While SAC will run on OS 10.6 using the 32-bit distribution, the SAC libraries in that distribution will not work in programs built using the 64-bit compilers that are the default for OS 10.6.
For licensing reasons IRIS cannot provide a Windows Cygwin binary distribution, but SAC can be built on Cygwin from a separately available Cygwin source distribution. However, as of Cygwin version 1.7, it is possible to build SAC on Cygwin using the normal source tarball.
A new feature that accompanies this release is that the SAC Users Manual has been updated. The format is different from before, but we think that everything is there that was on the earlier set of pages, and — unlike the earlier versions of the manual — the content of the pages are exactly the same as in the help files that one accesses directly from within SAC. Please report any questions/problems/suggestions regarding the manual to <snoke AT vt.edu>. (Unlike the releases of SAC, the manual can be corrected or updated very easily!)