Chapter 11: Mass Wasting

Mass Wasting, is the failure and downslope movement of rock or unconsolidated materials in response to gravity.  This term is sometimes referred to as “slope stability” and also commonly called “landslides.”  An important reason for learning about mass wasting is to understand the nature of the materials that fail, and how and why they fail so that we can minimize risks from similar events in the future. For this reason, we need to be able to classify mass-wasting events, and we need to know the terms that geologists, engineers, and others use to communicate about them. (1)

Mass Wasting in Arizona is common; far more common than most people think. The steepness of Arizona’s mountains, platueas, mesas, and buttes, coupled with intense rain through monsoon events, provides the perfect landscape for mass wasting to occur.  In the U.S., mass wasting events are a costly natural hazard, causing dozens of fatalities and ~$2–4 billions of damage to infrastructure, roads, buildings and homes annually (2).  Below you can see some images of recent mass wasting events in Arizona.

Arizona State Geological Survey, CC-BY