SKKH+2.3

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Vocabulary

 * After shock** -is a earthquake that occurs after a larger earthquake in the same area.
 * Liquefaction** -occurs when a earthquake violent shaking suddenly turns loose,soft soil into liquid mud.
 * Tsunamis -**a giant waved caused by an earthquke on the ocean floor. a biulding mounted.
 * Base-isolated building** -a biulding mounted on bearings designed to absorb the energy of an earthquake.

Outline
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How Earthquakes Cause Damage

 * The severe shaking produced by seismic waves can destroy or damage buildings,topple utility poles,and fracture gas and water mains.


 * Local Soil Conditions
 * Once seismic waves move hard dense rock to loosely packed soil,they transmit their energy to the soil making it shake more violently than the surrounding rock.


 * Liquefaction
 * When an earthquake's violent shaking turns ,soft soil into liquid mud ,it is called liquefaction. This is likely to occur where the soil is full of moisture.It can trigger landslides.


 * Aftershocks
 * An earthquake that occurs after a large earthquake in the same area is called an aftershock.


 * Tsunamis
 * Large waves caused by strong earthquakes are called tsunamis.

Making Buildings Safer

 * Choice of location
 * Construction Methods
 * To help a building withstand an earthquake,plywood sheets are used to strengthen the frames of wooden buildings.Bas-isolation bearings are used to reduce the amount of energy that reaches a building.

Protecting Yourself During an Earthquake

 * You should crouch under a sturdy table and hold on to it so it won't roll away.This table should protect you from falling objects.If no table is available than you should crouch against an innerwall and hold your head and neck

Diagram


This diagram shows how bas-isolated bearings help buildings.

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