As the plates of the earth move, three types of tectonic plate boundaries occur. Divergent boundaries occur when two plates move in opposite directions, such as the pulling apart of North and South America from Europe and Africa, which, according to the U.S. Geological Survey, happens at a ...
Learn about how the four different types of volcanoes (composite, shield, cinder cone, and lava dome) form and watch videos of how they erupt.