Chapter 5, Section 3 Earthquake Hazards and Safety Monday, February 15, 2010 Pages 162 -- 167.

Chapter 5, Section 3Earthquake Hazards and Safety

Monday, February 15, 2010

Pages 162 -- 167

Objectives

Distinguish between the kinds of damage an earthquake can cause.

Determine what can be done to reduce earthquake hazards.

Vocabulary Words

LiquefactionAftershockTsunamiBase-isolated buildingsDrop, cover, and hold

Affects of Earthquakes

Severe shaking produced by seismic waves can damage or destroy buildings, bridges, topple utility poles, and facture gas and water mains.

Earthquakes can also trigger landslides, avalanches, and hugh water waves.

Earthquake Hazards

Seismic waves transmit their energy from solid rock to loose soil.

Structures built on solid rock shake less than structures built on loose soil.

Liquefaction occurs when an earthquake’s shaking turns loose, soft soil into liquid mud.

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Earthquake Hazards -- cont’d

Aftershocks are smaller earthquakes that occur after a larger earthquake in the same area. Structures that have

been weakened by an earthquake may collapse during an aftershock.

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Original QuakeAftershock

Tsunami

Tsunamis are caused by earthquakes on the ocean floor.

The sea floor rises slightly and pushes the water out of its way.

This displaced water is a large wave called a tsunami.

Tsunamis spread out from the epicenter and rushes across the ocean.

Tsunami’s height increases when it reaches shallow water near land.

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Reducing Earthquake Damage

Most deaths and injuries in earthquakes are caused by damage to buildings and other structures. Stronger and more flexible buildings reduce

damage and injuries. Older buildings are modified to withstand

stronger quakes.

Reducing Earthquake Damage -- cont’d

Amount of damage that a structure suffers depends on the structure’s location and its construction. Buildings on steep slopes, filled land, or near a fault

should be avoided. Existing buildings should be reinforced. Base-isolated buildings are designed to reduce the

amount of energy that reaches the building during a quake.

Base-isolated buildings rest on shock-absorbing materials that reduce shaking during an earthquake.

Drop, Cover, and Hold

Drop, cover, and hold is the best way to protect yourself during an earthquake. This protects you from

falling objects and flying glass.

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Emergency Kits

Emergency kits is a must-have for people in high risk areas.

Emergency kits ensure that in the event that a quake happens, you will have the supplies to sustain yourself until help reaches you.

Emergency kits must be located in a place where it can be reached easily.

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Homework

Workbook 5.3 (2/12)Vocabulary quiz 5.3 (2/12)