San Andreas Fault, Part 4: Palmdale, Littlerock

By Dan Robinson Editor/Photographer

After turning off of CA-138 at Quail Lake, we temporarily leave the San Andreas fault zone to climb in elevation on Old Ridge Route Road. After about four miles, we're just past Sandberg and back along the fault zone. The fault zone lies in the field on the north side of Pine Canyon Road. As before, the time since the last earthquake means that the visible surface rupture has long been erased by erosion and vegetation. That of course will change when this segment of the fault ruptures again.

Click the “Sandberg” (with CTRL+click) for history and more info on ‘The Ridge Route’.

Lake Hughes, California

After passing Three Points, the fault zone generally runs directly underneath the road all the way to Palmdale. There are no obvious signs of the fault trace to be seen in these locations, although it is apparent that surface rupture from a future earthquake will do significant damage to this stretch of the road.

Lake Hughes town - photo credit to Dan Robinson & Stormhighway.com

Palmdale, California

In most locations, the San Andreas is not just a single fault. A complex network of mostly parallel faults often run on either side for some distance. Sometimes, these parallel faults will rupture in an earthquake instead of the main strand. Palmdale is one such location, famous in seismological circles for the Highway 14 road cut that exposes a fascinatingly detailed view of the folding and deformation of rocks along the numerous parallel faults in the area.

*It should be mentioned that near Palmdale is the small town of Neenach. In the hills is found 23.5 million year-old volcanic rock outcrops on the North American Plate. Add to that the SAF cuts right thru here. Check out the geologic story of our Pinnacles NP up north!

Littlerock, California

One should have no problem finding the San Andreas southeast of Palmdale, especially looking from some height. The soil and rocks on either side of the fault are of different colors, and the flora on each side is noticeably dissimilar.

In Part 5, Dan takes us into and thru the San Gabriel Mountains…