The creeping segment of the San Andreas fault extends from San Juan Bautista, the end of the northern segment
, to the Parkfield segment
. While elsewhere the fault is locked and moves in major earthquakes, here there is constant steady movement of about 3 centimeters per year and only minor quakes. Unlike the Hayward fault
, a creeping fault in a heavily populated built-up region, you can pull over, bring out your rock hammer and see it at leisure. There is also plenty of other geology along the way.
This tour follows state route 25 from Hollister almost all the way to Parkfield. Route 25 ends due east of King City, but the road continues under another name for another 25 kilometers. Beyond that the road along the fault is closed, and a detour is necessary. We end at Parkfield, in the Cholame Valley.
Follow the fault through this region on the interactive fault map at Thule Scientific, publisher of the excellent Field Guide to the San Andreas Fault.
San Andreas fault home page