Transform/Conservative Plate Boundaries At a transform plate boundary, two plates ‘Grind’ (or slide) past each other at ‘Transverse Faults’. As the plates grind past each other, they get ‘stuck’ against each other, eventually, as they continue to push together and create stress, a sudden jolt of movement occurs, this is an earthquake. The San Andreas Fault, on the west coast of North America is an example of a transform plate boundary. At this location, the Pacific and North American plates move towards each other so that the Pacific plate is moving in a north westerly direction – the motion of the plates is horizontal. The majority of transform boundaries are found on the ocean floor, near to active spreading ridges, in some cases, transform boundaries may cause the rise of mountains, for example, on New Zealand’s west coast, the southern alps rise beside the alpine fault. (Figure 1) (Figure 1)

This diagram shows how Transform Plate Boundaries rub against each other The San Andreas fault zone, is about 1,300 km long and in places, over 10 km wide. It slices through two thirds of the length of California. Along it, the Pacific Plate has been grinding horizontally past the North American Plate for 10 million years, at an average rate of about 5 cm per year. Land on the west side of the fault zone (on the Pacific Plate) is moving in a north westerly direction relative to the land on the east side of the fault zone (on the North American Plate). The speed of plates is very variable, for example, The Arctic Ridge has the slowest rate (less than 2.5 cm/yr), and the East Pacific Rise near Easter Island, in the South Pacific about 3,400 km west of Chile, has the fastest rate (more than 15 cm/yr).