The Southern California Earthquake Center (SCEC) exemplifies the type of large, geographically distributed collaboration becoming more common in scientific research. The SCEC community is more than 400 scientists from more than 50 organizations throughout the country and abroad who work together on the problems of earthquake science. To support this distributed community and improve its ability to transform basic research into practical applications, SCEC has initiated a Community Modeling Environment (CME) under the auspices of the NSF Information Technology Research (ITR) program (jordan et al. , 2003). The goal of the SCEC/CME is to develop a collaboratory that can aid practitioners in selecting, configuring, and executing the complex computational pathways needed for physics-based seismic hazard analysis.
In conjunction with the CME project, SCEC and the U.S. Geological Survey (USGS) have jointly developed OpenSHA (Field et al. , 2003), an open-source, object-oriented software framework for probabilistic seismic hazard analysis (PSHA). OpenSHA provides users with a number of well accepted and widely used PSHA software components, including attenuation relationships and earthquake rupture forecasts (ERF's). Earlier this year, we began integrating into the OpenSHA system one of the most sophisticated ERF's ever developed, the WGCEP-2002 model for earthquake probabilities in the San Francisco Bay area (WGCEP, 2003). This task presented us with some software development challenges that called for distributed computing. We investigated and evaluated a variety of technologies, and the lessons we learned in obtaining a useful and robust solution may be of interest to our colleagues.
Three factors motivated an implementation based on distributed computing: First, the WGCEP-2002 ERF is written in FORTRAN, and we wanted to access it from our existing, Java-based, OpenSHA applications. Second, this ERF requires a lot of computer cycles and memory. Third, and most significant, the OpenSHA framework was explicitly designed for scientific collaboration. The OpenSHA …