Chapter 5, Section 3 Earthquake Hazards and Safety Monday, February 15, 2010 Pages

Objectives Distinguish between the kinds of damage an earthquake can cause. Determine what can be done to reduce earthquake hazards.

Vocabulary Words Liquefaction Aftershock Tsunami Base-isolated buildings Drop, 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.

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. Original Quake Aftershock

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.

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.

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.

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