The occurrence of a threatening condition derived from a natural phenomenon in a defined space and time can be considered as a natural hazard (Alcántara-Ayala, 2002). It is important to understand, however, that the damage produced by such hazards can extend beyond the exact moment when they occur. In other words, they could have a significant impact in the long term. The notion of natural hazards is very frequently associated with geological, geophysical and hydrometeorological processes; nonetheless, as they are mostly significant constituents of the Earth's surface dynamics, they should be also viewed and analyzed from a geomorphological viewpoint.
Physical phenomena, such as volcanic activity, seismicity, flooding and landsliding, turn into hazards when they pose a danger to landscapes, both cultural and natural. Cultural landscapes are shaped from a natural setting by a cultural group, where culture is the agent, the natural area is the medium, and the cultural landscape the result (Sauer, 1925). While geomorphology aims at the understanding and appreciation of landforms and natural landscapes (Bauer, 2004), from a practical point of view it also recognizes and understands the processes and landforms that are related to dangerous conditions.
Different conceptual terms have been addressed in order to define and comprehend the complexity of natural landscape evolution: endogenic–exogenic forces; destructive–constructive action; erosional–depositional forms; stress–strength relationships, and polygenesis and inheritance (Bauer, 2004). By virtue of their nature, geomorphological hazards can be understood by means of all those concepts.