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Corporate Partners: Unlocking the Secrets of Earthquakes

By Rhonda Hillbery

The Division of Geological and Planetary Sciences' new Computational Facility is brimming with computers so powerful that they will comprise one of the 10 most powerful computer clusters in the academic world.

So it's not surprising to learn that the 2,048-processor "machine," housed in the South Mudd Laboratory basement, is expected to pack enough computing power to help unlock the mysteries of powerful and often devastating earthquakes.

According to Jeroen Tromp, McMillan Professor of Geophysics and director of the Institute's Seismo Lab, who spearheaded the $5.8 million parallel computing project, corporate gifts of computers and equipment were instrumental in making it possible. Dell and Myricom both made partnership donations of computing components, and Intel provided a generous gift in support of the project.

In the new Computational Facility, hardware that arrived over the summer fills long rows of black racks, each containing about 35 computer nodes. Massive air conditioning units line an entire wall of the 20-by-80-foot room to recirculate and chill the air. Meanwhile, miles of cable tie the processors together into a working cluster that went online in September 2005.

The corporate support provided the lead funding necessary for Tromp and his colleagues to secure additional funds from the National Science Foundation. "The other crucial ingredient was Caltech's investment in the infrastructure necessary to house the new machine," he says. Some 500 kilowatts of power and 90 tons of air conditioning are needed to operate and cool the hardware. According to David Kewley, the project's systems administrator, that's enough kilowatts to power 350 average households.

Tromp's research group will share use of the cluster with other division professors and their research groups, while a job-scheduling system will make sure the facility runs at maximum possible capacity.

Tromp, who arrived at Caltech in 2000 from Harvard, is known as one of the world's leading theoretical seismologists. Until now, he and his Institute colleagues have used a smaller version of the machine, popularly known as a Beowulf cluster (off-the-rack components that run on a free Linux operating system). Helping revolutionize the field of earthquake study, Tromp has created three-dimensional simulations of seismic events. He and former Caltech postdoc Dimitri Komatitsch designed a computer model that divides the earth into millions of elements. Each element can be divided into slices that represent the earth's various geological features.

In simulations involving tens of millions of operations per second, the seismic waves are propagated from one slice to the next, as they speed up, slow down, and change direction according to the earth's characteristics. The model is analogous to a CAT scan of the earth, allowing scientists to track seismic wave paths. "Much like a medical doctor uses a CAT to make an image of the brain, seismologists use earthquake-generated waves to image the earth's interior," Tromp says, adding that the earthquake's location, origin time, and characteristics must also be determined.

The new Computational Facility will increase computing power and speed by one order of magnitude. That means Tromp will be able to deliver better, more accurate models in less time. "We hope to use the new machine to do much more detailed mapping. In addition to improving the resolution of our images of the earth's interior, we will also quantitatively assess the devastating effects associated with earthquakes based upon numerical simulations of strong ground motion generated by hypothetical earthquakes."

"One novel way in which we are planning to use the new machine is for near real-time seismology," Tromp adds. "Every time an earthquake over magnitude 3.5 occurs anywhere in California we will routinely simulate the motions associated with the event. Scientific products that result from these simulations are 'synthetic' seismograms that can be compared to actual seismograms."

The "real" seismograms are recorded by the Southern California Seismic Network (SCSN), operated by the Seismo Lab in conjunction with the U.S. Geological Survey. Of interest to the general public, Tromp expects that the collaboration will produce synthetic ShakeMovies of recent quakes, and synthetic ShakeMaps which can be compared to real ShakeMaps derived from the data. "These products should be available within an hour after the earthquake," he says. The Division also hopes to renovate the Seismo Lab Media Center, and install a huge video wall on which scientists can show the results of simulations and analysis.

The new generation of seismic knowledge may also help scientists, engineers, and others lessen the potentially catastrophic effects of earthquakes. "Without the Dell, Myricom, and Intel contributions, this project would never have happened," says Tromp.

Caltech is seeking $850,000 to complete the project. For more information, please contact Mark Reinecke in Caltech's development office at 626-395-3707 or mreinecke@caltech.edu