Physcial weathering <span>is the process that breaks rocks apart. So, I suppose when an earthworms digs and tunnels their way through the soil? They move the broken peices of rock causing it to break into smaller peices.</span>
Since the formation of the San Andreas Fault system 25-30 million years ago, the juxtaposition of the Pacific and North American plates has formed many faults in California that accommodate lateral motion between the plates.
hope this helps