Table of Contents
What is a slump mass movement?
slump, in geology, downward intermittent movement of rock debris, usually the consequence of removal of buttressing earth at the foot of a slope of unconsolidated material. It commonly involves a shear plane on which a back-tilting of the top of the slumped mass occurs.
Are slumps slow moving?
Most slumps develop over comparatively longer periods, taking months or years to reach stability. An example of a slow-moving slump is the Swift Creek Landslide, a deep-seated rotational slump located on Sumas Mountain, Washington.
Does a landslide move fast or slow?
How fast do landslide travel? Landslides can move slowly, (millimeters per year) or can move quickly and disastrously, as is the case with debris flows.
How do you identify a slump?
Slump material moves as a whole unit, leaving behind a crescent shaped scar. Figure 2. Trees with curved trunks are often signs that the hillside is slowly creeping downhill. Creep is the imperceptibly slow, steady, downward movement of slope-forming soil or rock.
What is the slowest type of mass movement?
The slowest type of mass movement is creep. This occurs on slopes where there is significant plant or tree growth.
Which type of mass movement takes place gradually?
Creep. Soil creep is a slow and long term mass movement. The combination of small movements of soil or rock in different directions over time is directed by gravity gradually downslope. The steeper the slope, the faster the creep.
What happens during a mudslide?
Mudslides develop when water rapidly accumulates in the ground and results in a surge of water-saturated rock, earth, and debris. Mudslides usually start on steep slopes and can be activated by natural disasters.
Is a landslide slow?
Soil that moves downhill slowly is said to “creep”, and its movement is often slow and shallow enough to be anticipated and managed with a modest effort. A third type of landslide is “rotational.” It, too, can be slow, but it is a deep movement of the soil, and its effects can be devastating; for example, the 1973 Mt.
What is a slow moving landslide called?
Also known as earth flows, slow-motion landslides are actually more common than fast-moving landslides. As the name suggests, slow-motion landslides are landslides that are slow moving. Some of these types of landslides move as slowly as one meter per year.
Where are slumps most common?
Slump is common where clay-rich materials are exposed along a steep slope. Such oversteepend slopes naturally occur on the outside of meanders along the Red River. Slump is typically identified as the downward movement of a block of earth material along some curved surface of failure.
Which mass movements is the fastest?
Landslides and avalanches can move as fast as 200 to 300 km/hour. Figure 3. (a) Landslides are called rock slides by geologists. (b) A snow avalanche moves quickly down slope, burying everything in its path.
What is the slowest but most common type of mass wasting?
The most common form of mass wasting is creep.
When does a slump occur in a slope?
Slumps often happen when a slope is undercut, with no support for the overlying materials, or when too much weight is added to an unstable slope. Figure 1. Slump material moves as a whole unit, leaving behind a crescent shaped scar. Figure 2.
How long does it take for a slump to develop?
The speed of slump varies widely, ranging from meters per second, to meters per year. Sudden slumps usually occur after earthquakes or heavy continuing rains, and can stabilize within a few hours. Most slumps develop over comparatively longer periods, taking months or years to reach stability.
Which is an example of a slow moving slump?
An example of a slow-moving slump is the Swift Creek Landslide, a deep-seated rotational slump located on Sumas Mountain, Washington. Slumps may also occur underwater along the margins of continents and islands, resulting from tidal action or a large seismic event. These submarine slumps can generate disastrous tsunamis.
How does rain affect the rate of slumping?
Rain provides lubrication for the material to slide, and increases the self-mass of the material. Both factors increase the rate of slumping. Earthquakes also trigger massive slumps, such as the fatal slumps of Turnagain Heights Subdivision in Anchorage, Alaska.