Using seismic tomography to help reduce earthquake risks

Thomas Jordan came to USC — where he is University Professor and the W. M. Keck Foundation Professor of Geophysics in the USC College of Letters, Arts and Sciences — to run the Southern California Earthquake Center (SCEC), a leading consortium of earthquake researchers at more than 40 universities and other institutions that is headquartered at USC. Founded in 1991 and funded by the National Science Foundation and the United States Geological Survey, the SCEC gathers information about earthquakes in Southern California, integrates it into a comprehensive, physics-based understanding of earthquake phenomena, and communicates the results to the public to increase earthquake awareness, reduce economic losses and save lives.

SCEC also participates in a National Science Foundation Information Technology Research Program for the development of an online "collaboratory" system that organizes information about earthquakes and allows scientists to conduct their research interactively and efficiently. SCEC's information technology researchers are developing new architectures and software programs that integrate several research-oriented technologies, including grid-based programs, Web services and digital libraries.

Jordan and his research group specialize in seismic tomography, using seismic waves from naturally occurring earthquakes to create three-dimensional computer images of the earth's crust, much as doctors use sound and other waves to image the human body. Before the installation of HPCC's Linux cluster, Jordan's group did their computing on workstations. Processing one of the thousands of sampling functions needed to create a seismic tomography image took them approximately three days. Using the HPCC Linux cluster, the same computation takes less than 20 minutes. As a result, Jordan's group has been able to go from one-dimensional to two- and three-dimensional images that will help them locate hotspots in Southern California where intense shaking during earthquakes could cause major damage. Such research has the potential to enhance the information that engineers use when designing quake-resistant buildings, bridges and power plants.