Volcanoes make new land. Rifts on continents can create valleys, as is seen in the East African Rift Valley. But it means that in your lifetime, North American will move westward the length of a man's body. When two plates move toward each other, the denser one is forced under the other in a process called subduction. Deep trenches are formed when subduction happens in the ocean, also it gives rise to earthquake activity and volcanic islands.
Japan is such a place, in the Pacific Ring of Fire.
Right now, India is colliding with the Eurasian Plate, causing the Himalayan Mountains. Plates may also slide past each other, like what is happening in the western United States. The San Andreas fault in California is where the Pacific plate slides past the North American plate. Continental Drift Plate tectonics helps explain the theory of Continental Drift. That theory states about 175 million years ago all the continents of the earth moved together in a single giant landmass.