Parkfield Fault Model (IMAGE) California Institute of Technology Caption This image shows an array of geodetic instruments at the surface of Earth and activity that was modeled on the fault below. The yellow colors indicate the highest speeds of slippage between plates along the San Andreas Fault. The reddish colors represent slower seismic speeds and the bluish colors indicate slippage at velocity close to the long-term advance of the San Andreas Fault. The dark color indicates a portion of the fault where the velocity is so small that it appears completely locked. Credit Sylvain Barbot / Caltech Usage Restrictions Credit required License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.