Final answer:
The San Andreas Fault divides the Pacific and North American Plates, running from the Gulf of California to north of San Francisco, and is responsible for significant earthquakes and tectonic activity in the region.
Step-by-step explanation:
The fault that divides the Pacific and North American Plates is known as the San Andreas Fault. This transform boundary extends from the Gulf of California up to the Pacific Ocean northwest of San Francisco. It is notorious for being the site of major slippages, which can lead to destructive earthquakes.
The movement of the Pacific plate northward is significant, as it carries major cities like Los Angeles and San Diego with it.
Over several million years, this motion could potentially make Los Angeles an island positioned off the coast of San Francisco. The San Andreas Fault is part of the larger Ring of Fire, a zone of earthquake and volcanic activity where the Pacific plate meets other tectonic plates.