Account for the theory of plate tectonics.?

The earth's crust (land and water) basically sits on a sea of liquid molten rock or "mantle." The different plates are moving around on the surface of this. We tend to think of only tectonics on land, but it's even more prevalent under the oceans, hence tidal waves. Earthquakes result when the pressure between two plates "snaps." Volcanoes are where the mantle has broken through the crust. The plates actually move up and down, north and south, and east and west. So some areas are moving away from each other while other plates are pushing against each other. Some plates are pushed up as another slide moves under others leading to mountain ranges. The short term effects we are seen as earthquakes, over millions of years it leads to mountain ranges

As for accounting for the theory, billions of years ago all the continents were one. Just compare the Eastern South American coast to the West coast of Africa to see how these could have lined up. What initiated the movement? My guess is a one or more massive meteors slammed into the earth and broke up the crust into multiple fragments. Think of a glass cup breaking when its dropped, there are multiple shards and some end up on top of each other, others lay beside each other, and the size of the pieces varies. In plate tectonics the shards are held to the surface of the earth due to gravity. Because of the size of the earth is so huge we can barely appreciate this movement in our lifetime. But the same process is occurring.