Transcript Controlling Constructive and Destructive Forces

Seismological Studies
0 Earthquakes are mostly destructive. Scientists
work hard to prevent damage caused by
earthquakes.
0 They used tools to monitor movement in the
Earth's crust. A seismograph records movements
in Earth's crust. The data helps them identify
places that are most likely to be affected by
earthquakes. It also helps engineers determine
which materials and construction designs are best
able to resist the shaking.
Seismological Studies
0 A seismograph is used to measure the
movement of the ground during an earthquake.
The seismograph makes waves on a piece of
paper that show how much the earth shakes.
0 Richter Scale
Scientists use the information provided by a
seismograph to determine the severity of an
earthquake. The Richter Scale scores
earthquakes from 1 to 10 depending on the
amount of movement that the earthquake
causes.
Flood Control - Dams
0 Dams help control the flow of water down major
rivers. That flow of water is then turned into electricity.
The Tennessee Valley Authority, which was created as
part of FDR's New Deal, built many dams in the
Southeastern U.S. They still are a major source of
hydro-electric power today.
West Point Dam
Flood Control - Levees
0 A levee is a structure designed to prevent or
control flooding. They are designed to control the
flow of water. Unlike dams, they do not block a
river. Instead they make the sides of the river
taller to prevent flood damage to nearby cities,
houses and businesses.
Flood Control –
Storm Drain Management
0 Heavy rainfall can lead to large amounts of water
running through the city's storm drain system. As
more and more people live in cities, pollution
becomes a bigger and bigger problem.
0 Building a drain system helps a city prevent minor
flooding.
Beach Reclamation (Georgia
coastal islands)
0 Waves erode sand from Georgia's beaches each day.
Currents and storms also cause beach erosion.
0 Sand moves away from some beaches and builds up
on others. The moving sand fills in channels, which
become too shallow for boats to pass through.
0 The process of replacing sand on a beach is called
beach reclamation, or beach restoration.
0 Cumberland Island, located near Georgia's border
with Florida, dredges sand out of channels and
dumps it onto the beach.
Beach Reclamation
Dredging
Spreading sand to restore beaches
Beach Reclamation - Jetties
0 Jetties are built to protect the beach from erosion.
Jetty on Tybee Island
Georgia’s Barrier Islands
0 Sometimes ocean currents and
waves deposit sand and dirt just
offshore from the mainland. Over
many years, these deposits may
build into a new landform known
as a barrier island. Scientists
refer to them as barrier islands
because they form a barrier
between the sea and the land.
0 Georgia's barrier islands are often
called the Golden Isles. They
stretch from the Savannah River
in the north to the St. Mary’s
River in the south.