Close Researchers can not determine when and where exactly an earthquake will occur. But, a new study that utilizes supercomputer power accounts for the unique characteristics of the faults in the area, allowing seismologists to better understand what threats in Southern California might exist. (Photo : Masterpress/Getty Images) Large earthquakes are infrequent. We simply haven't seen such quakes on most California faults, says Kevin Milner, a computer scientist at the Southern California Earthquake Center and lead author on the new study. The fact that most faults in California have not hosted a large damaging earthquake since modern records have been kept, says Milner, leaves researchers "to infer what types of earthquakes we think are possible on those faults." This uncertainty creates challenges for hazard assessment and planning.