Plate Tectonic theory: Earth's outer shell consists of individual plates that interact in various ways and thereby produce earthquakes, volcanoes, mountains, and the crust itself.
The difference between Plate Tectonics Theory and Continental Drift is that the Continental Drift theory never had evidence while the PTT had evidence to prove it such as Paleomagnetism, Earthquake Patterns, Ocean Drillings, and Hot Spots
Evidence to prove Plate Tectonics Theory
Paleomagnetism - We have evidence that Ocean plates are moving because when they do it creates Normal polarity "strips" and reverse polarity "strips" showing that magma is forming and then cooling to creature new rock
Earthquake Patterns - Scientist have found that there is a strong connection between deep focus earthquakes and Ocean trenches showing that they are connected some how because when a deep focus earthquakes happen another shallow focus earthquake happens adjacent to a trench.
Ocean Drilling - Sediment from drilling showed that the increase of sediment age grew with increasing distance from a ridge. The youngest crust is at ridge crust and the oldest is at continental margins
- Hot spots - As plates move over hot spots successive volcano mountains have been created and as it moves it creates new ones showing that the earth plates aren't still.