How might a large moving body like a continent look along its forward moving edge and its trailing edge? Now obtain maps of the eastern and western portions of the United States and trace the shoreline along both coasts.

Describe and discuss similarities and differences between coastlines. You should find a relatively straight Pacific coastline and a highly irregular Atlantic coastline with numerous islands and waterways.

The west edge, the forward moving edge of the continental block, is thought to be ramming against and riding over the eastern edge of the Pacific Ocean floor, while the eastern edge is dipping and trailing behind. Two bricks on blocks can be used to demonstrate how the North American continent block might be riding over the Pacific Ocean block.

As the bricks are moved, breakage occurs in the boundary zone between the two blocks, and internal stresses in the earth build up and are periodically released as earthquakes.

San Andreas; it's not my fault.