ACTIVITY TWO
L
ANDSLIDES
: S
LIP
-S
LIDING
A
WAY
RA T I ONA L E
Earthquakes dramatically increase the potential for landslides in areas
where landslides are common, such as those where sedimentary rocks
lie just under the soil. Structures on cliffs and ridges need to be
designed to the highest earthquake standards, and should be fully
insured.
F OCU S QU E S T I ON S
How can an earthquake trigger a landslide?
What factors affect the probability of an earthquake-related landslide?
OB J E C T I V E S
Students will:
1. Construct a model to simulate an earthquake-related landslide.
2. Investigate the variables that affect an earthquake-related landslide,
such as the strength of the slope materials, the steepness of the slope,
and the intensity of ground shaking.
3. Explain why the steepness of a slope determines how the force of
gravity acts on an area of ground and how it is related to frictional
forces.
MA T E R I A L S
for the teacher
Q
Slides or photos of landslide damage (in your geographic area, if
available)
Q
Slide projector and screen or blank wall space (
optional
)
Q
Pasteboard or cardboard arrows in three colors, cut to the correct
lengths to illustrate the 30° angle (
optional
)
for each small group
TEACHING CLUES AND CUES
Q
A pine board, approx. 2.5 cm x 25 cm x 1.0 m (1 in. x 10 in. x 3 ft.)
Q
A meter stick
Q
Two plastic dishes, approx. 19 cm in radius, with sides 3.5 cm high
The width of the board
can vary, but it must be
1 m long.
Q
Enough dry sand to fill the two dishes
Q
500 ml of water in a beaker or other suitable container
Q
Newspapers to cover work surfaces
Q
A sensitive bathroom scale that can register weights as low as 1
The inexpensive clear
plastic dishes sold to put
under potted plants will
be ideal. The dish must
Newton (less than 2 lbs)
Q
Paper towels for cleaning the board between trials
be a little smaller than the board.
Q
Master 2.4c, Landslide Data Table
Q
Master 2.4d, Landslide Activity Sheet
A G U
/
F E M A
92
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E I S M I C
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L E U T H S
