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Announcing Open Source SAC Community Edition v103.0

Tags: data services

Our community’s access to the Seismic Analysis Code (SAC), which has been brilliantly maintained for years by Brian Savage and Arthur Snoke after its fork from LLNL’s SAC2000, is now being released as open source software as the SAC Community Edition. This change is a departure from the restrictive license under which EarthScope previously distributed SAC and is part of our ongoing commitment to supporting access to open software.

What’s Changing

Starting with SAC Community Edition v103.0 the source code is being released with an open license (Apache v2).  The source code is available through our GitHub repository:

https://github.com/EarthScope/sac-community

As in the past, we maintain neither the source code, the executable binaries, nor the documentation of SAC. These tasks were undertaken by Brian and Arthur who, after many years, have retired from this role. When someone volunteers to take on the role of SAC maintainer(s), Brian has graciously offered to transfer knowledge of the system.

Why is SAC Changing to an Open License?

Until recently, SAC software was under a license that prevented distribution to users from certain countries.  More recently, permission was received to release a new version of SAC under an open software license.  To do that, a new version of the software had to be released so that it is distinct from the previous restricted version (v102.0).  This new version can be distributed to anyone, copied, modified, and used AS IS within the terms of the new, open license.  It should be noted that this release is a distinct fork from LLNL’s own SAC2000 open source release, so we invite you to also look at their repository if you find that they offer features that you need:

https://github.com/llnl/SAC2000

What You Need to Do

  • If you are currently using a version of SAC that is under the restricted license, you must continue to abide by the terms of that license.  
  • If you are able to download and compile a version of SAC under the open license, or use any binaries distributed from the same repository, you may use and distribute the source code and the binary openly.
  • If you wish to add a feature to SAC, you may do so and distribute that new version either openly or as a commercial product within the terms of the new, open license.

If you have any questions about the SAC Community Edition software distribution try asking in the SAC Community mailing list:

https://groups.google.com/a/earthscope.org/g/sac-community

If you would like to volunteer as a SAC Community Edition maintainer please contact our Help Desk at help@earthscope.org.

Thank you for your continued support in making great geophysical software more accessible and impactful.