Over the course of more than 20 years, the Seismic Analysis Code was developed at the Lawrence Livermore National Laboratory, first as a Fortran code (simply named SAC), then ported to C and renamed SAC2000. SAC2000 has evolved as the seismologist’s primary tool for the analysis of earthquake signals (Goldstein et al., 2003). Concerned that SAC2000 is likely the major vehicle for the processing of data resulting from USArray while at the same time its maintenance and development is in the hands of LLNL without any formal input from outside users, a session at the IRIS workshop was held to discuss SAC2000 and its future within the IRIS community.

Peter Goldstein from LLNL, who has been responsible for SAC2000’s recent development, gave a brief overview of new technical capabilities of SAC2000, and of its flexibility to adapt to the needs that may arise from USArray, e.g. interfacing it with real-time input of array data. It is clear however, that developments that do not directly serve the interest of LLNL (mostly concerned with treaty monitoring), will not be supported by LLNL. Session participants showed a strong interest in an active development of SAC2000 and discussed ways to do so.

Peter Goldstein sounded moderately optimistic that legal obstacles to make the source code available to others would disappear in the near future. One of the options discussed was that larger modifications could be effected by way of subcontracts financed by IRIS or others, whereas smaller improvements might be contributed by the user community and incorporated after review by a steering committee.

As a next step, the DMS standing committee is soliciting views from the user community. A brief report outlining the various realistic options for SAC2000’s future will be prepared before IRIS budget for the next fiscal year is discussed. IRIS members who are interested to participate in this process or who would like to offer views on this issue should contact Guust Nolet (nolet@princeton.edu).

References

Goldstein, P., D. Dodge, M. Firpo, and L. Minner (2003). SAC2000: Signal processing and analysis tools for seismologists and engineers. IASPEI International Handbook of Earthquake and Engineering Seismology, ed. W. H. K. Lee, H. Kanamori, P. C. Jennings, and C. Kisslinger. Amsterdam & Boston: Academic Press.