Processes That Shape Earth

Evidence for Future Landslides and Solutions

Can people predict landslides? Visible evidence of erosion, such as
new boulders at the base of a slope, can be a warning sign. Tilting
trees or other objects, including poles, can indicate that a slope is
about to give way.

Exposed roots in a hillside mean some of the slope has already eroded, possibly in a
landslide. Boulders and other fallen debris at the base of a slope are another sign that
erosion is occurring and a large-scale landslide may soon occur.

Natural Solutions
One way that some communities have tried to solve the problem
of mudslides and landslides is to plant more vegetation. Some
types of vegetation have roots that grow deep and strong in the
soil, causing the soil to cling together. This makes landslides less
likely. But events such as wildfires followed by a heavy rain can
clear an area of vegetation and make it more likely that landslides
will happen. In some areas, people have built walls or terraces on
hills to make landslides less likely.

45

Human-Made Solutions

Communities that are
vulnerable to landslides
can reduce some of the
hazards they face. A
home that is going to
be built on a slope can
be protected by having
a retaining wall above
and below the house.
These walls change a
steep slope into something more like a staircase. Each level holds a
certain amount of sediment.

Another technique is to

use concrete and steel

pillars to support hillside

structures. These pillars

can be anchored into

solid bedrock so the

structures are more likely

to stay in place even if the

looser sediment tumbles How would these structures help reduce or prevent
down the slope during a landslides?

landslide. The foundation remains anchored to the part of Earth’s

surface that does not collapse. However, it is possible that the

debris flow could crash into the structure and knock it off its

secure foundation.

46

Glossary

E mass movement, n. downhill movement of a
mass of earth surface material (41)
earthquake, n. shaking of the ground caused
by a seismic wave (13) metamorphic rock, n. rock that forms when
igneous or sedimentary rock is placed
erosion, n. movement of sediment from one under tremendous heat or pressure (7)
location to another (33)
P
F
plate, n. in geology, a large fragment of Earth’s
fossil, n. the remains of an organism preserved crust and upper mantle (3)
in rock form (1)
S
G
sediment, n. small pieces of rock or other hard
geologist, n. a scientist who studies what material that has broken down over time
Earth is made of and how it changes over (33)
time (1)
sedimentary rock, n. rock made of sediment
H compacted together (6)

hot spot, n. in geology, a plume of magma sinkhole, n. a hole in Earth’s surface that
that causes eruptions through Earth’s crust develops when the ground collapses into
without plates interacting (29) space beneath it (37)

I T

igneous rock, n. rock made of magma or lava tsunami, n. a wave or series of waves caused
that has cooled and hardened (7) by displaced water (19)

L V

landslide, n. a form of mass movement in volcano, n. an opening in Earth’s crust
which a large section of a slope slides through which lava erupts onto the surface
downhill all at once (41) (25)

lava, n. molten material from Earth’s mantle W
after it has reached Earth’s surface (27)
weathering, n. the process of breaking rock
M into smaller pieces (36)

magma, n. molten material from Earth’s
mantle below Earth’s surface (27)

magnitude, n. the size or extent of an
earthquake (17)

47



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