landslides and sinkholes Flashcards
(19 cards)
A _________ is defined as the movement of a mass of rock,
debris, or earth down a slope.
landslide
_______ are a type of
“mass wasting,” which denotes any down-slope
movement of soil and rock under the direct influence of
gravity.
Landslides
Landslides have three major
causes:
geology, morphology, and human
activity.
________ refers to
characteristics of the
material itself.
Geology
The earth or
rock might be weak or
fractured, or different layers
may have different strengths
and stiffness.
Geology
_________ refers to the structure
of the land.
Morphology
__________ holds soil in
place, and without the root
systems of trees, bushes, and
other plants, the land is more likely
to slide away.
Vegetation
_________ , such
as agriculture and construction,
can increase the risk of a
landslide.
Human activity
Types of Landslide
In _________, heavy
blocks of material fall after
separating from a very steep
slope or cliff. Boulders
tumbling down a slope would
be a ________.
falls and topples
In ________, surface
material is separated from the
more stable underlying layer of
a slope.
An earthquake may
shake the loosen top layer of
soil from the harder earth
beneath in this type of
landslide.
translational slides
A ___________ or flow is the
movement of material sideways,
or laterally. This happens when
a powerful force, such as an
earthquake, makes the ground
move quickly, like a liquid.
lateral spread or flow
A _________is a depression in the
ground that has no natural external
surface drainage.
sinkhole
Sinkholes are most common in what geologists call, “______ terrain.”
karst
These
are regions where the types of rock below the land surface can naturally be
dissolved by groundwater circulating through them.
karst terrain
__________ are most commonly seen in areas that have
a very thin cover of soil on the surface, exposing the bedrock
below to continual erosion by water.
may collapse all of a sudden, other times it happens over time.
Solution sinkholes
These take place when the bedrock is covered by a deep layer
of soil and earth.
usually
happens in a sudden manner and can create large holes in a
matter of minutes.
Cover Collapse
In this case, the hole is formed over a period of time
Cover Subsidence
Collapse
____________ sinkholes occur due to erosion or
underground water. They start developing
long time before it actually appears.
Natural
Activities like drilling, mining, construction,
broken water or drain pipes, improperly compacted soil
after excavation work or even heavy traffic can result in
small to large sinkholes
Man-made
