Divergent plate boundaries occur where two tectonic plates move away from each other. This movement creates new crust as magma rises from the mantle to fill the gap. These boundaries are often found along mid-ocean ridges, such as the Mid-Atlantic Ridge, where the ocean floor is formed. As the plates separate, earthquakes can occur, and volcanic activity may be present. The formation of new oceanic crust at divergent boundaries contributes to the process of seafloor spreading, which plays a crucial role in the Earth's geological activity and the movement of continents over time.