It was a good day yesterday to visit the Hayward fault at the top of Chabot Road. The previous night’s rain softened the ground and left the cut weeds smelling like fresh hay. This is the view north from the ground above the end of the road.
All of this land is suspect today, and the rocks cannot be trusted. The high ground I was standing on is the rubble pile built to support Route 24. The high ground on the right is an old excavation or rubble pile, I’m not sure which, supporting the loop linking Route 24 west and Route 13 south. The flat ground is the former roadbed of the Oakland & Antioch Railway. The trees in the distance are on a rocky slope that roughly marks the Hayward fault, but it may well have been quarried in the past. The nice thing about a fault, for producers of crushed rock aggregate, is that it pre-crushes the rocks. But the fault is somewhere in this view, although it’s poorly mapped between the Claremont Resort and Montclair.
With that preamble, I feel free to speculate that the fault trace could possibly nip Chabot Road at its farthest end. We see displacement of the curbs, and at the farther joint we see evidence of compression. In both photos the near side would be west of the fault, moving leftward.
But just as likely, this trodden, retreaded land is shifting and settling all by itself. There may be slow landsliding involved. Also, heavy trucks and other vehicles could well have done this damage. The truth may come out after the next big earthquake ruptures the fault here. It’s one place I want to check out in the aftermath, if I’m lucky enough.