Answer:
The lithospheric plates move over the asthenosphere layer due to the generation of convection current in the mantle. It is due to the heat provided by the interior of the earth. These plates move in the opposite directions in a divergent plate boundary, due to which the seafloor spreading takes place resulting in the formation of the Mid-Atlantic Ridge and new materials are added to the crust. The earthquakes of deep focus are generated due to this divergent plate motion. For example, the Mid-Atlantic Ridge is the feature produced due to the separation of the ocean floor.
The divergent motion of continents or separation of continents due to the divergent plate motion is known as the continental divergent margin. One of the best examples is the Great Rift valley.
When the lithospheric plates move towards each other, then it forms a convergent plate boundary. It results in the formation of a subduction zone, that is marked by the deep sea oceanic trenches and deep-focus earthquakes are generated. One of the famous examples is the San Andes mountain due to the collision of the Pacific Plate and the South American plate.
In a transform plate boundary, the two plates side past one another, and there occurs no destruction or creation of crust. It results in the shallow focus earthquakes. For example, the San Andreas fault is formed due to the transform margin between the Pacific and the North American plate.