What is the main type of tectonic plate boundary that exists along the edge of the north american plate near the coast of northern california

To the east, the North American plate shares the Mid-Atlantic Ridge with the Eurasian plate. This divergent margin, offset throughout by transform faults, began spreading approximately 180 Ma ago, opening the North Atlantic Ocean. Evidence of Mesozoic juvenile crust formation in New England can be correlated with the event.

Explanation:

The San Andreas transform boundary between the Pacific and North American plate originates from the shallow, oblique subduction by the North American plate of the Monterey microplate

The Monterey-Pacific ridge stopped spreading and Monterey accreted to the Pacific plate. As a result, the Pacific plate's motion with respect to the North American rotated, transforming a network of shallow faults into dextral transform faults