Transcript earthquake - Trimble County Schools

Essential Questions
• What is an Earthquake?
• What is a Tsunami?
• What Causes Earthquakes?
• What are the Effects of
Earthquakes?
What is an Earthquake?
• An EARTHQUAKE
occurs when part of the
Earth’s crust suddenly
shifts. In an earthquake, a
sudden release of energy
inside Earth sends waves
moving upward and
outward. These waves
shake the ground.
Earthquakes form cracks
and faults along the
surface.
Earthquakes
• Earthquakes often
cause other
natural disasters
– Fires sometimes
occur
– Tsunamis can start
as a result of the
powerful
earthquake
Tsunamis
• Earthquakes which occur on the ocean floor
produce giant sea waves called tsunamis.
Tsunamis can travel at speeds of 700 to 800
km per hour. As they approach the coast,
they can reach heights of greater than 20
meters.
Causes of Earthquakes
• Plates shift in earth’s outer crust.
• Stress occurs on rocks along
faults.
• Excessive stress causes rocks to
break.
• Rocks move into new positions.
• This causes the shaking of
earthquakes.
Where most Earthquakes occur…
San Andreas Fault
• The San Andreas fault extends
960 km from Mexico to the
north of California.
• The land to the west is moving
north. The land to the east of the
fault is moving south. All the
rocks do not move at the same
time so earthquakes occur in one
area and then another.
How Earthquakes Move
• Looking at this picture, A represents
the EPICENTER- the place in which
the earthquake started. Waves travel
outward from the epicenter. B
represents the first city that will
experience the effects of the
Earthquake.
Interesting Fact
• Earthquakes
rarely kill
people …
• Building
collapses do!
Interesting Fact
• Even buildings
left standing
are dangerous.
• There is often
structural
damage.
Effects of Earthquakes
• People are
often left
homeless.
• They must
find
temporary
housing.
Effects of Earthquakes
• Looting
(stealing) often
takes place.
• Chaos usually
makes things
worse.
• Police patrols are
necessary.
Devastating Examples
from History
• San Francisco’s famous
earthquake of 1906
• Quake caused damage to some
buildings.
• Other buildings were undamaged.
• Look at some scenes from 1906.
San Francisco, California Earthquake
Of 1906
Let’s Review
• What other major natural disaster
do earthquake sometimes cause?
a) Volcanoes
b) Tsunamis
c) Hurricanes
d) Tornadoes
Let’s Review
• What causes strong earthquakes
to happen?
– A.) A strong earthquake is caused
by a sudden slip on a fault
– B.) A strong earthquake is caused
by people, as in explosions
Let’s Review
• The region of the United States
with the most earthquakes is...?
– A.) the North
– B.) the South
– C.) the West
– D.) the East
Let’s Review
• Earthquakes usually happen along
cracks in the earth's crust called...?
– A.) Jagged lines
– B.) Fault Lines
– C.) Layers
– D.) Wrinkles
Let’s Review
EXTENDED RESPONSE
• As we’ve learned- earthquakes are
a fast-moving change to Earth’s
surface. Discuss at least five things
about the destructiveness of
earthquakes.
• Include any or all of these:
– Causes
– Effects on people or land
– Examples