Describe the types of plate boundaries and give examples, including fold mountains and the San Andreas Fault.

Looking at FIGURE 3.5, the arrows between the South American Plate and the African Plate indicate that they are moving away from each other. This type of boundary is where new crust is formed.
The common border between the South American Plate and the African Plate is a constructive plate border.

At a constructive plate boundary, plates move apart, allowing magma to rise from the mantle and solidify, forming new oceanic crust. This process is known as seafloor spreading.

Fold Mountains are formed at convergent plate boundaries, typically where an oceanic plate subducts beneath a continental plate (oceanic-continental convergence) or where two continental plates collide. The immense compressional forces cause the crustal rocks to fold, fault, and uplift, creating mountain ranges along the continental margins.

The fault plane in California on which Los Angeles and San Francisco are situated is the San Andreas Fault.

The San Andreas Fault is a transform plate boundary where the Pacific Plate and the North American Plate slide horizontally past each other. Due to friction, stress accumulates along the fault as the plates attempt to move. When this stress exceeds the strength of the rocks, they suddenly slip, releasing energy as seismic waves, which we experience as earthquakes. The frequent occurrence of these earthquakes and the measurable displacement of land features over time provide direct evidence of the continuous, albeit sometimes jerky, movement of Earth's tectonic plates. This constant motion and the resulting seismic activity clearly demonstrate that plate movement is actively taking place.