Talc Might Lubricate San Andreas Fault

There is currently a major project going on to drill into the San Andreas Fault to better understand the various mechanisms of the fault system. The project is organized and run by SAFOD, the San Andreas Fault Observatory at Depth. Recent cores have shown that a layer of talc is located approcimately 2 miles below the ground surface. Members of the SAFOD speculate that the talc may act as a lubricant for the San Andreas Fault and the occurrence of the layer may explain the absence of sharp earthquakes. Check out the article in the San Francisco Chornicle, and expect to see the full results published in the Journal Nature.