The San Jacinto Fault: Little Brother of the San Andreas January 19, 2006

In southern California, the San Andreas fault splits into two different faults, the San Andreas and the San Jacinto faults. Both have produced large earthquakes in the past. The San Andreas is older, but just like a little brother, the San Jacinto is becoming more active and trying to outdo the San Andreas. In this presentation we will explore the risks associated with these two faults and examine the evidence for the relative activity of each fault. How do geologists study ancient earthquakes and find out how quickly faults moved in the past? We will look at the underground views of faults, and how we read the history that is preserved there.

http://pasadena.wr.usgs.gov/info/lectures/