How Technology and Humans Help
Control Earth’s Processes
Being Prepared for Earthquakes
• Scientists use instruments called
seismographs to measure seismic waves.
• Seismographs can help predict when and
where an earthquake may occur, but it
cannot prevent them.
Earthquakes Cont’d
• Engineers, Architects, and Scientists work to
construct buildings and bridges that can
withstand powerful earthquake shaking
• Buildings are built on springs and sway rather
than break and fall
• People who live in high risk zones can practice
drills and have emergency kits ready
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A dam is a structure built across a stream or
river to retain water.
Some dams are tall and thin, while others are
short and thick.
They are made from various materials: rock,
steel, soil, sand, concrete, or wood.
Dams help control flooding downstream.
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A levee is a mound of earth or other materials
that is built along the sides of rivers.
Levees help control floods.
A
system of drains that
prevent flooding along roads
and other land
BEACH RECLAMATION
A lot of erosion happens on coasts.
 Coastal erosion eats away at beach sand.
 People help reclaim beaches in these four
ways:

 Groin
 Seawall
 Jetty
 Beach
Nourishment
GROINS

Groins are built at right
angles to the beach
and trap sand moving
along longshore
currents.
GROINS
SEAWALLS

Seawalls are built parallel to the shore to
absorb the pounding of waves.
JETTY

A jetty is a wall-like
structure that sticks
out into an inlet to
prevent sand from
being carried away.

As longshore currents
move along the coast,
the jetty traps sand
and small rocks.
BEACH NOURISHMENT

Beach nourishment reclaims beaches by
adding more sand from the ocean or nearby
rivers to help rebuild it.
GEORGIA’S
GOLDEN ISLES
Do the Golden Isles
serve a purpose in
protecting Georgia’s
mainland? If so, what
is it?
 Terracing
• Planting crops on terraces built on hillsides
 Contour
Plowing
• farming across the sides of hills