earthquakes 6

7/25/2019 Earthquakes 6

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EARTHQUAKES


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EARTHQUAKES

When ENERGY released

from the moving crustallates! the surroundingroc" la#er trem$les and

shifts% This movementsis called earth&ua"e%


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The shifting or movement of the crustallates give rise to tectonic

earth&ua"e% When magma movesalong a 'ssure! the# cause the Earth(scrust to trem$le! too% The magma ma#reach the surface and )hen this

haens! a volcanic erution occurs%Earth&ua"es caused $# volcanicactivit# are called volcanicearth&ua"es%


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Eicenter is the oint on thesurface of the earth locateddirectl# a$ove the center of anearth&ua"e(s origin% Thecenter or source of the

earth&ua"e is called focus%


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Earth&ua"eTerminolog#


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What causesearth&ua"es*

Elastic Re$ound

Sources of stress +late Tectonics

,ther stresses


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When the crust sha"es! such tremorcauses damages to eole! $uildings!$ridges! roads! and vegetation% The

e-tent damage caused $# anearth&ua"e is called its .NTENS.TY%

.NTENS.TY/usuall# measured in therossi/forel scale% This scale ranges

from intensit# i/i-% This scale $ased onthe e0ect of the tremor on eole ando$1ects%


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2AGN.TU3E 4 is the amount of energ#released $# an earth&ua"e% AnAmerican scientist named 5harles 6%

Richter develoed a scale to indicatethe magnitude of an earth&ua"e%The R.5HTER 2AGN.TU3E S5A7E that

uses num$er 8 to 89% The stronger the

earth&ua"e is! the higher the num$er ofthe scale% The more fee$le or )ea"erearth&ua"e roduce a lo)er magnitude%


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2easurement 2agnitude

one er earth&ua"e related to energ# released

Richter or 2oment scale

.ntensit# man# for each

earth&ua"e

measure ofe0ects

2ercalli scale


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3amage: 5auses Ground motion

3uration ofSha"ing

Surface Ruture

+oor $uildingdesign


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E0ects Ruture

3eath ;ldg collase


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E0ects 6ires

7i&uifaction 7andslides


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3amage:

Ke#6actors

Amount < duration of sha"ing Water content of soil

+oulation concentration

;uilding construction

3istance from Eicenter

3eth of focus

3irection of ruture

2aterial amli'cation


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Addressingthe Ha=ard

.dentif# areasat ris"

6orecast


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Addressingthe Ha=ard

Structuraladatations

Warning s#stems


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Scientists have invented a devicethat measures the movement of theearth(s crust% .t is called

seismograh% .t can detect andrecord the vi$rations on the earth(ssurface%


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A seismograph isan instrumentused for recordingthe intensity and

duration of anearthquake.


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Earth&ua"e Safet# Tis

;E6,RE AN EARTHQUAKE:

Choose a safe place in every room such as under asturdy piece of furniture like a table or a desk wherenothing can fall on you.

Practice DROP CO!"R A#D $O%D O#&' Drop under something sturdy hold on and protectyour eyes by pressing your face against your arm.

Prepare a disaster supplies kit for your home and car.(nclude a )rst aid kit canned food and a can openerbottled water battery'operated radio *ashlightprotective clothing and written instructions on how toturn o+ electricity gas and water.


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3UR.NG AN EARTHQUAKE:

DROP CO!"R A#D $O%D O#&

,tay indoors until the shaking stops.

,tay away from windows.

(f you-re in bed hold on and stay there protectingyour head with a pillow.

(f you-re outdoors )nd a clear spot away frombuildings trees and power lines. hen drop to theground.

(f you-re in a car slow down and drive to a safeplace. ,tay in the car until the shaking stops.


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A6TER THE SHAK.NG ST,+S:

Check for in/uries.

(nspect your home for damage.

"liminate )re ha0ards so turn o+ the gas if youthink its leaking.

"1pect aftershocks.

"ach time you feel one DROP CO!"R A#D $O%DO#.


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EARTHQUAKES

The sha"ing of the crustal lates$rought a$out the release of

energ# from the earth(s interior%


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earthquakes 6

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