Transform Boundaries

Transform boundaries are the places where Earth’s crust is neither created nor destroyed. Instead, two plates simply slide horizontally past each other. This is the key idea that separates transform boundaries from the divergent and convergent boundaries you have already studied.

The planes along which this sliding happens are called transform faults. These faults are not random cracks; they are generally perpendicular to the mid-oceanic ridges. In other words, they cut across the ridge system at right angles, connecting one segment of the ridge to another.

Why do these faults form in the first place? The mid-oceanic ridge is not a single, continuous crack that erupts all at once. Eruptions do not take place along the entire crest of the ridge at the same time. Because of this, different portions of the plate move at different rates. One part of the plate may be pushed away from the axis of the earth while another part lags behind. This creates a differential movement — different sections of the same plate moving at different speeds or in slightly different directions.

On top of this, the rotation of the earth also exerts an effect on these separated blocks of the plate. The spinning of the planet influences how the broken-off portions of the plate behave, adding another layer of complexity to their motion. …