Answer:
Evidence that these earthquakes occur along a transform plate boundary is that the plates slip past each other at the boundary.
Step-by-step explanation:
The San Andreas Fault is one of the most active places on Earth when it comes to earthquakes. This fault runs through California in a roughly north-south direction and is the most problematic place in this part of the United States when it comes to earthquakes. Faults like this one form only at transform plate boundaries and that's the case in here as well.
The North American plate and the Juan de Fuca plate move in opposite directions, but they do not collide, instead, they slide past each other. By sliding past each other there is constant pressure along the boundary, resulting in cracking of the crust, both on the surface and deep inside. With the crust cracking, gaps open up, and the crust from above falls further down to fill it in, and by doing so enormous amount of energy is released, manifested through vibrations, better known as earthquakes.