There is one thrust fault running from Dodger Stadium underneath Downtown Los Angeles straight down to Long Beach that is capable of producing a 7 plus earthquake. It called the Puente Hills Fault. It was discovered after the 1994 earthquake.
San Diego SuperComputer visualization Services....Puente Hills
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Puente Hills Fault posses a disaster threat for Los Angeles region. Earthquake simulations on this fault estimate damages over $250 billion. The research was conducted by U.S. Geological Survey (USGS) and Southern California Earthquake Center (SCEC). More information about the study could be found at the SCEC research webpage .
Visualizations created by using the data computed from earthquake simulations helps one to fathom the propagation of siesmic waves and the areas affected. Animations were created using SDSC's Vista volume renderer, Alias's Maya and Adobe's After Effects.