The San Andreas fault is an example of which type of tectonic plate boundary?
A. divergent
B. convergent
C. transform
D. collision
The correct answer and explanation is:
The correct answer is C. transform.
The San Andreas Fault is a well-known example of a transform boundary, which occurs when two tectonic plates slide past one another horizontally. At transform boundaries, there is no creation of new crust or destruction of old crust, as is seen in divergent or convergent boundaries. Instead, the plates simply move laterally along the boundary, causing stress that leads to earthquakes.
In the case of the San Andreas Fault, it forms the boundary between the Pacific Plate and the North American Plate. The Pacific Plate is moving northwestward, while the North American Plate is moving southeastward. This lateral motion results in significant strain along the fault, and the plates do not move smoothly. As they get stuck due to friction, pressure builds up over time, eventually releasing in the form of an earthquake.
The movement along a transform boundary like the San Andreas Fault is not vertical, unlike convergent boundaries where one plate is forced beneath another, or divergent boundaries where plates move apart. Instead, the plates move horizontally relative to one another. This horizontal motion often causes significant geological features like fault lines, and in the case of the San Andreas Fault, it has created long, linear valleys, cliffs, and other surface features that can be traced along the fault line.
Understanding transform boundaries helps explain the origin of many earthquakes, particularly in areas like California, where the San Andreas Fault is located. The movement along these fault lines is a critical part of the seismic activity experienced in the region.