Geography of the United States
The Americas have been moving west for over 100 million years. The movement has buckled up and collected geological plates in the West, and spread out the land in the East. This has resulted in a series of mountain ranges all down the West of the Americas, and mostly low-lying land in the East. The East is a "passive margin" coast where the continental crust is moving away, in this case to the West. The West is an "active margin" coast. It has the mountains and it has the landslides and volcanoes.