- © 2005 by the Seismological Society of America
We present seismic-hazard calculations for what is arguably the most sophisticated earthquake forecast ever developed—the model by the 2002 Working Group on California Earthquake Probabilities (2003), or WGCEP-2002 as referred to hereafter. These calculations have been made possible by developments in both OpenSHA (Field et al., 2003) and the Information Technology Research (ITR) Collaboration of the Southern California Earthquake Center (SCEC) (Jordan et al., 2003). In particular, we demonstrate the use of a freely available, platform-independent, and graphical-user-interface-based application for computing hazard curves. This application utilizes distributed-object technologies, meaning the code running on the client's computer communicates over the Internet with code hosted elsewhere on server computers. This interoperability, which is invisible to the user, makes the application fast and executable without heavy installation requirements. Instructions on how to reproduce the calculations presented here are available under “Publications” at the Web site http://www.OpenSHA.org/.
OpenSHA (Field et al., 2003) is a collaborative effort between SCEC and the United States Geological Survey (USGS). The goal has been to develop a “community modeling environment” or “collaboratory” for seismic hazard analysis (SHA), where any arbitrarily complex model component can be plugged in for analysis (without having to change what is being plugged into). This is a departure from previous approaches in which PSHA code (typically FORTRAN) would be rewritten for each new application. Developing a more flexible “plug and play” environment is particularly important in that proper SHA requires that all viable models be considered in the analysis (SSHAC, 1997).
As the name implies, OpenSHA is an open-source development, meaning anyone is free to examine the code. It is also object-oriented (enabling the plug-and-play modularity), platform-independent, accessible via a graphical user interface (GUI), and potentially network-distributed. These features have been achieved using the Java programming language. There is no …