TRANSVERSE versus TRANSFORM FAULT

Look at the figures below as if you are looking down from a helicopter:
west north
south 		east

Imagine the red line is a highway, and the blue line crossing it is a fence.
In the left figure, take points A and B to represent the single point

where the fence crosses the highway
In the center figure, points A and B have moved relatively to each other,
as represented by the arrows
This situation is referred to as a left lateral transverse fault
(if you follow the fence and come to the road, you have to turn left to find the continuation of the fence)
Point A sits and remains on the yellow segment (left = west), point B on the blue (right = east).

Looking only at the red and blue lines and the letters A and B,

note the similarity of the center figure and the figure on the right
Imagine now that the blue line - formerly a fence- is a sea-floor spreading center
from which molten magma extrudes and moves away (see arrows)
Also note that only between the offsets (points A and B) are the "yellow" plate
and the "blue" plate moving in opposite directions along the red line,
which represents a fault. This will cause earthquakes.
Note that both north of A and south of B, the motions on either side of the fault are similar, so no earthquakes
Furthermore, since the spreading centers are high and slope downward away, there will be scarps facing opposite directions along the fault: if you stand at point A on the spreading center you'd look down to the west, while if you'd walk eastward along the southernmost spreading center (dark blue line) and reach point B, there would be a steep drop before you could continue onto the blue plate. Somewhere half-way between A and B, you could just step across the "transform" fault from the one plate to the other without having to do any climbing! I guess that's why it is much easier being a fish.
BLO fecit 20021024 - use your BACK BUTTON to return - J. Tuzo Wilson