Produced by Dr. M. Mustoe
Geographer
This page and its graphics are ©1997 by M. Mustoe

The above pictures would obviously look neat as animations. However, they have not been animated to stress a point. The point is that this movement takes place over tremendous amounts of time and in some cases continues on into the present. But what we see of these landforms seems frozen in time and what changes we (usually) see are extremely small in the context of the overall system. But don't think of these as static landform expressions because they are continually being transformed.

Grabens are the subsidence of the land between two normal faults. These can be hundreds of miles in length. Some well known grabben valleys are the Red Sea Basin, the Alamosa Valley of Colorado, The Rift Valley of East Africa. Horsts, are the (relatively rare) oppoistes of grabbens. A horst is an uprisings of a fault block with scarps on either side. Obviously what is represented here takes a great deal of time and will erode and weather with age. But, keep in mind that erosion begins to act on the land's surface from the on-set of any movement whatsoever.

click the seismogram to go back to the fault page