Just a few days after I started working at a deep underground hard rock mine as a geotechnical engineer, a double fatality happened. Two miners carrying a heavy pump up a decline were killed by a rockfall. Investigation that took place described the accident as “unpredictable” and stated that the support was adequate for the prevailing conditions. One day, soon after the rockfall, whe I was walking up the decline, I noticed that at that particular spot there were some wet patches at the back and some water trickling at one sidewall.

Geomorphology is the study of earth-surface processes and forms. As a component of the fields of geology and geography, geomorphology is particularly concerned with change: progressive changes through time or changing spatial distributions at the earth’s surface. Geomorphology as a science views the objects of its study as collections of elements in complex systems that are groupings of forms and related processes. Because these groupings have regional manifestations strongly controlled by geologic materials and structures, the geomorphic systems of North America have a definable regional expression that serves as a method of organizing knowledge. The Geological Society of America’s publication series celebrating the Decade of North American Geology and the Centennial of the founding of the organization is generally organized according to geographic regions, so it is appropriate that this companion volume to the series also adopts a regional framework (Figs. 1 and 2).

The geomorphologic divisions of the continent depicted in Figure 2 are broad generalizations. Discussions in subsequent chapters that more specifically define the extent of each division use boundaries suggested by workers several decades ago.

The word “geomorphology” is derived from the Greek roots geo (Earth), morphos (shape), and logos (study). Thus, geomorphology is the study of the shape of the Earth’s surface. Schumm (1991) defines geomorphology as the science of phenomena on or near the earth’s surface and the interactions between different types of materials and processes, including solids, liquids and gases. The effects of human activity are often crucial. Some authors consider geomorphology to be one of the most difficult physical sciences (Linton, 1964). Some authors restrict geomorphology to the study of the characteristics of sub-aerial topography but others extend it to the morphology of the ocean floors. Geomorphology also includes the investigation of landforms on other planets; this science is called planetary or extraterrestrial geomorphology (Greeley, 1985; Baker, 1981a; 1993, 2001, 2004a).