Transcript Earthquake Damage Unit

Earthquake Damage Unit
Where would you be the safest in an
earthquake?
• Open level field away from buildings
• Movement of the ground rarely causes deaths or
injuries
• Deaths and injuries result from collapse of
buildings or structures, flying objects and glass
• Landslides, fires, explosions caused by broken
electric and gas lines and floodwaters from
broken dams also cause death and injuries
• A moderate earthquake that continues for a long
time can cause more damage that a shorter
earthquake of higher magnitude
Destruction of Buildings and
Properties
• Buildings with weak walls may totally collapse
• Tall buildings sway so violently they tip over and
destroy anything around them
• Type of ground a building is built on affects
whether or not a building survives
• Buildings built on loose soil and rock is more
likely to be damaged than one built on solid
ground
• On what type of ground should a tall building in
an earthquake – prone region be constructed?
Tsunamis
• Giant ocean wave caused by a major earthquake with an epicenter
the ocean floor
• May be caused in two ways
• Faulting- causes a sudden drop or rise in the ocean floor
• A large mass of sea water also drops or rises with the ocean floor
• This water then churns and causes violent movement of water
resulting in a Tsunami
• Underwater landslides – water above a landslide is thrown into an
up and down motion creating a series of tsunamis
• 1964 Alaskan earthquake: tsunami caused 107 deaths and only 9
people died as a result of the earthquake
• Seismograph stations now also monitor sea waves to warn of
impending tsunamis
Earthquake Safety
• Before an earthquake occurs be prepared
• What are some ways in which you could be
prepared? Supply of canned food, bottled
water, flashlights, batteries and portable radio.
Have a plan. Learn how to turn of the gas,
electricity and water in your home.
• Stay calm
• Move to a safer position
Earthquake Safety Cont.
• Where do you think a safe position would be?
Indoors, stand in a doorway or crouch under a
desk or table. Stay away from windows, heavy
furniture and other objects that might topple
over. Do out run outside. If you are in a car
drive away from tall buildings, tunnels and
power lines, bridges and stay in your car.
• After an earthquake be cautious
• Check for fire hazards
Earthquake Warnings and Predictions
• Animal behaviors – earliest means of
predicting earthquakes
• Animals appeared nervous and restless
• Scientists are trying to detect changes in the
earth’s crust that can signal an approaching
earthquake.
• Place instruments along rocks in faults
• They can detect rock movement and increase
in stress
Earthquake Warnings and Predictions
• Seismic gaps place where the fault is locked and
unable to move
• Stress in surrounding rocks has increased and no
major earthquake has occurred in this location
for at least 30 years
• Scientist believe seismic gaps are likely locations
of future earthquakes
• Several seismic gaps exist along the San Andreas
fault
• Slight tilting of the ground shortly before an
earthquake can be used as a prediction
Study Questions for Earthquake
Damage Unit
• How do tall buildings usually respond during a major earthquake?
• What causes tsunamis?
• What should you do if an earthquake strikes while you are at
home? In a car?
• What are some early warning signs of earthquake activity?
•
What type of building construction and locations regulations
should be included in the building code of a city located near an
active fault?