Poorly written, not wrong. It’s the San Andreas fault which the author descripes as being in southern California. Loma Prieta is just north of center, near the northern limit of San Andreas’ intersection with California.
No Loma Prieta is at least 90 miles from where the San Andreas heads out to sea. Most of the San Andreas is in what is geographically known as Northern California. (Basically that which is north of the ridge line of the Tehachapi)
Also, very little of the plate moved significantly during that quake; just portions in Santa Cruz and Santa Clara counties. The rest of the plate had already made its move long before.