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?