Mass wasting refers to the movement of soil, rock, and debris downslope under the force of gravity. It is a type of erosion and can occur rapidly, such as in landslides, or slowly through creeping. Mass wasting is influenced by many factors like slope angle, rock type, climate, vegetation, and pre-existing weaknesses in the slope material. It poses hazards through loss of life and property damage, often greater than earthquakes or volcanoes. Proper slope management through stabilization techniques and monitoring can help prevent mass wasting events.

1. Add a SlideTitle - 1
MA S S
WA S T I NG

2. MASS WASTING
soil, rock debris,
and/or bedrock
move in bulk at the
Earth’s surface
it is form of erosion
/ transportation
controlled by
gravity

3. MASS WASTING
Why it is
important?
account for more loss
of life and property
damage than do
earthquakes and
volcanoes
should be aware of the
signs and hazards
when buying a home

4. MASS WASTING
Examples

5. Examples
LandslideinMakilala,
Cotabato

6. Examples
LandslideinMakilala,
Cotabato

11. https://www.youtube.com/wat
ch?v=g5Y_O6I5mu8
TyphoonVamcoTriggers Landslides in the
PhilippinesAmid Heavy Wind and Rain
https://www.youtube.com/wat
ch?v=69q23-R-FSA
https://www.youtube.com/wat
ch?v=y-LCCAxEngo
Landslide inToledo City
SuperTyphoon Causes Landslide
https://www.youtube.com/wat
ch?v=CGtBTpP5vhg Pinatubo Eruption

12. Factors controlling mass
wasting
weight of material
normal force
shear force
shear strength
friction
cause of mass
wasting
gravity

13. MASS WASTING
WATER:
Critical Factor
The potential for mass
wasting is
DIRECTLY RELATED
to the amount of
water in the material.

14. MASS WASTING
WATER:
Critical Factor
A small amount of
water
Too much water
Water adds weight

15. MASS WASTING
WATER:
Critical Factor
Freeze / thaw
The expansion /
contraction of debris
can cause creep

16. MASS WASTING
Controls and
Triggers
Oversteepening of
slopes – slope angle
Stable slope
angle
Unstable slope

17. MASS WASTING
Classification
TYPE OF
MATERIAL
Debris
Bedrock

18. MASS WASTING
Classification
TYPE OF
MOVEMENT
Flow
Slip
Fall

19. MASS WASTING
Classification
RATE OF
MOVEMENT
Creep
Flows and Slides
Falls and Avalanches
landslides

20. MASS WASTING
TYPES
Debris Flow
Mudflows /earthflows
Slips and Slides
Rock Slides
Slumps
Debris slides and
slumps
Falls
Rock Falls
Debris Falls

21. MASS WASTING
TYPES
Movement of a mass of
rock or unconsolidated
material as a unit along a
curved surface.
Occurs along over
steepened slopes
Slumps
https://www.youtube.com/
watch?v=OVUtAmJf1qI

22. MASS WASTING
TYPES
Consists of soil and
regolith with a large
amount of water
Often confined to
channels
Debris Flow (mudflows /
earthflows)
https://www.youtube.com/watch?
v=Fsh5E9m3PrM&list=PLdp6P_64
WQcZj3G0dbJE1YVd_HDGWk_Pr
&index=2
Material flows like a
viscous liquid
Lahars =
a special
type

23. MASS WASTING
TYPES
Blocks of bedrock
slide down a slope
Rock Slides
https://www.youtube.com/
watch?v=rV1Aj-7F8SQ
Moving along
planes of weakness
Generally very fast
and destructive

24. MASS WASTING
TYPES
Debris slides and
slumps
https://www.youtube.com/
watch?v=riNhJdtkakg
Coherent mass moves
along plane of weakness
Debris slumps -
rotational

25. MASS WASTING
TYPES
Rock Falls
https://www.youtube.com/
watch?v=SPU7gPN4hfc
Rocks freely fall
from cliffs.
Caused by wave
action, human activity
or from frost heaving
along steep cliffs.

26. MASS WASTING
Influencing
Factors
Slope Angle
Rock type
Vegetati0n
Climate
Planes ofWeakness

27. Influencing
Factors
Slope Angle
Steeper slopes = higher shear
force
Relief
Difference in highest and
lowest elevations
Higher relied = moving masses
build up more momentum / speed

28. Influencing
Factors
RockType
Loose debris = less stable than
solid rock
Vegetati0n
Roots hold debris together
More vegetation = more
stable

29. Influencing
Factors
Climate
Frequent precipitation =
inhibits mass wasting
Frequent precipitation =
inhibits mass wasting
Heavy or intermittent precipitation
= may enhance mass wasting
https://www.youtube.com
/watch?v=gpyqWiFz9p8

30. Influencing
Factors
Pre-existing
weaknesses
Frequent precipitation =
inhibits mass wasting
Foliations = metamorphic
rocks
Bedding = sedimentary rocks
Sheet joints / cooling joints /
fractures and faults
Parallel =
unstable
Perpendicular
= stable

31. What to look
for or consider
Look for signs of creep or any
other mass wasting
Look for planes of weakness
Consider consequences of
over steepening slope
Beware of removal of
vegetation
Consider addition of weight
Systems such as sprinkles that
add water

32. Prevention
Stabilizing slopes
Retaining walls with adequate
drainage
Planting vegetation to hold
material together
Rock bolting – to bedrock
Removing unstable slopes
Minimizing extra weight