Mass Wasting is a term that used by geologists to describe the movement of rocks and soil down a slope under the force of gravity. It is sometimes refered to as slope movement or mass movement. Some of this movement can take the form of years, where a large mass moves slowly down a hill. It can also be extremely rapid, such as a toppled stone, or even a stone avalanche.
This chart shows a number of different ways that this takes place.
I made the chart above, as a compilation of a few charts that I have seen. to help describe and illustrate different types.
Topple: Is where a large rock, series of rocks, or blocks fall away from a slope. This is very common in many areas where stone is worn away, especially under other stones. Eventually the heavy stone above it will weaken and just topple over. Sometimes rolling down a slope. They can be identified by the few stones that have fallen laying about.
Rock and Soil Creeps: These are slow, taking a long time. In fact they may be difficult to pinpoint. They move slowly dowhill with gravity slowly pulling on them. The steeper the slope the faster the creep. Sometimes they may turn into land or rockslides. This tends to be why hills are rounded. Think of taking a cone, filling it with mud and turning it upside down. You can do this with dirt, but the mud is faster and more dramatic. Holding together to dome outward.
Rockslide, mudslide, or debris Flow: These are moderately fast slides of of rocks, or other debris. They are common after storms or in a fire area where the water loosens the material and send it downhill. Mudslides and debris flows are espeically common after a fire. The fire removes much of the plant life that holds the soil in place. A sudden buildup of water in the soil can cause it to move down the slope in mudflows or debris flows. There will be debris area for them, quite often in fan shapes at the base, where they flow outward.
Rockflow or Avalanches: These are rapid and large movements of materials. The material may cascade rapidly downhill and cause a vast amount of damage. A Rockflow is tumbling of just rock down a hillside, Rock Avalanche is similar with a lot of soil includes, while a debris avalanche tends to be made up primarily of finder materials. These tend to have large rockfall, debris fields
A slump: This is a weakening of the soil on a slope, it causes the soil to slide away. Not as slow as a creep that the movement may take decades, but not as rapid as a debris flow. Usually caused by a lot of water loosening the soil then in a process that may be fairly rapid, or a few inches a day it will slide. Usually it will will just drop. A quick way to tell if it is a some other ground flow and a slump is how trees may fall. In a slump they typically fall backward, the roots on the downward side.. The deep slumping of the ground pulling it down and and the roots forward. In many other flows trees are still deeply anchored and pushed over from the uphill. Causing the roots to be uphill.
At this location there are a few spots to stop and identify what kind of mass wasting is/has been taking place
Location A (at these cordinates)
Question #1: What are a few of the causes of the Earth movement here?
Question #2: What type of movement would you identify this as? and why?
Location B (N 39° 24.715 W 111° 22.639) Scattered about this area are a number of large stones?
Question #3: How would you think they traveled here, and from where?
Question #4: What type of movement would you identify this as? and why?
Location C (N 39° 24.500 W 111° 22.578 ) Looking to the North East
Question #5: What is the makeup of the debris (size, amount, etc)?
Question #6: What type of movement would you identify this as? and why?
