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Chapter 16: Unsafe Ground: Landslides and Other Mass Movements
Animations
Click on the links below to view animations created specifically for Earth: Portrait of a Planet. Animations require Macromedia's Flash Plug-in.
ANIMATION: Cliff Retreat along the Coast
This animation illustrates the process by which undercutting by waves removes the support beneath an overhang. Eventually the overhang breaks off along joints, a rock fall occurs, and the cliff retreats. For more information, see see Section 16.3 Why Do Mass Movements Occur? starting on p.565 and Figure 16.19 on p. 571 in your textbook.
Zoomable Art: Mass Movement
In Earth's gravity field, what goes up must come down—sometimes with disastrous consequences. Rock and regolith are not infinitely strong, so every now and then slopes or cliffs give way in response to gravity, and materials slide, tumble, or career downslope. This downslope movement, called mass movement, or mass wasting, is the first step in the process of erosion and sediment formation. For more information, see the Featured Painting on pp. 572-573 in your textbook.