A little about Erosion and how it happens in many different ways. Erosion Facts and description of how erosion works, also looks at human impact and significance. Geysers A geyser is a hot spring that periodically erupts throwing water into the air. Seems simple and common enough, but in fact, geysers are extremely rare. In all of the world, there are only a total of seven hundred geysers.
Site is mostly in text and very scientific, but contains lots of facts.
Learn the basics behind plate tectonics and what causes the plates to move. The Story of Plate Tectonics On-line version of the book from the U.S. Geological Survey. This site has information on how rivers are formed and other physical aspects of rivers, as well as case studies of the Singapore River and the Rhine. Volcanoes A summary of the nature, workings, products, and hazards of the common types of volcanoes around the world, along with a brief introduction to the techniques of volcano monitoring and research. This site has all the information you might want about volcanoes and plate tectonics.