The ground under Los Angeles is always in motion. This video shows a series of unfelt microquakes as bursts of color plotted along a 15-kilometer-long, 20-kilometer-deep piece of the Newport-Inglewood fault complex. The action has been sped up by a factor of 150.
This video is adapted from "Earthquake Waves in Your Neighborhood," presented by Professor of Geophysics Robert Clayton at Caltech's 75th Annual Alumni Seminar Day on May 19, 2012. Read the full story at http://features.caltech.edu/features/391