Searching for Frictional Heat with Fission Track Thermochronology

The San Gabriel fault isn't as hot as we thought -- frictional heat generated during fault slip at this location was not hot enough to be recorded by fission track thermochronology

Project Summary Motion along faults, regardless of their coefficient of friction, should release large amounts of energy. Laboratory experiments of sliding surfaces show that while some of the energy goes into mechanical processes (such as grain-size reduction) and the radiation of seismic waves, a large majority of it is dissipated as heat. This project endeavors to find evidence of this heat using low temperature thermochronometry on the rocks around exhumed faults. We collected samples along a transect across the San Gabriel fault zone, an ancient and abandoned trace of the San Andreas fault system. We see no evidence for frictional heat in these samples and therefore estimate that the effective coefficient of friction on the fault must have been less than 0.4.

Tools sledgehammer, chisel, fission track thermochronology, numerical modeling of heat transport around faults

Geographic Location San Gabriel fault zone near Little Tujunga Road, southern California

Group Members Involved Matthew d'Alessio <Email> <Personal Web Site>
Ann Blythe (University of Southern California), Roland Bürgmann

Project Duration In Progress (began in 2001)

More Information < Project Web Site >