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Chapter 11 Earthquakes and Volcanoes
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Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Mar 26, 2015

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Page 1: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Chapter 11

Earthquakes and Volcanoes

Page 2: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

EarthquakesThe shaking caused by the sudden

movement of the crustScientists estimate that over one million

earthquakes happen every year.Approximately one earthquake every

thirty seconds.Most so small that no one notices them

are recorded by seismographs.

Page 3: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Several thousand per year actually move the surface of the Earth.

About 20 per year cause severe changes in the Earth’s surface.

These have the potential to cause serious damage to buildings and dramatic loss of life in populated areas.

Page 4: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Seismic WavesWaves travel from the break outward.Main cause is faulting. If they occur on the ocean floor they can

cause giant waves called tsunamis– Travel at 700-800km/hr– 10 to 20 meters high when they hit the

coast.

Page 5: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Seismic Waves

Focus- where the rocks break– below ground

Epicenter- the surface directly above the focus.

Where shaking is worst

Page 6: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Seismic wavesThree typesPrimary waves- P waves

– Fastest– Travel through solid, liquid, and gases– Pressure wave

Secondary waves- S waves– slower– Don’t go through liquids– Shear waves - side to side

Page 7: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Seismic wavesSurface waves- L waves

– slowest– Move like ocean waves - rise up and

down– cause the most damage

Page 8: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 9: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 10: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 11: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

SeismographDetects and

measures seismic waves

Seismogram is the record made by it

Studied by a seismologist

Flat line - no motionBigger waves,

stronger quake

Page 12: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

                           

                           

Page 13: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Richter scaleHow we compare the strength of

earthquakesNot a machineNumber from 1 to 10Higher number stronger earthquake.Every 1 number higher is 10 times

strongerBigger than 6 very destructive

Page 14: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Predicting EarthquakesTo be useful must predict

– where– when– how strong

Not very goodmake buildings differently in earthquake

areasTrying by measuring motion of earth,

speed of waves, tilt of earth, electricity

Page 15: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

VolcanoesMagma- melted rock below the surfaceLava- when it reaches the surfaceVolcano - where lava reaches the surfaceLava lets us see what is below the crustDifferent types of lavaDark colored, runny lava flows quietlyLight colored hardens inside, pressure

builds and it explodes.Gas bubbles can form pumice and scoria

Page 16: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Rock fragmentsThrown out in eruptionsDifferent sizesVolcanic dust- like flourVolcanic Ash- grains of riceCinders- about the size of a golf ballVolcanic bombs- a few centimeters to

several meters across

Page 17: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Types of VolcanoesThree different typesCinder cone formed by piling up rock

fragments from explosive eruptionsNarrow base and steep sidesShield volcanoes runny lava pouring out

covers the ground in layers large area, gentle slope - Hawaii

Page 18: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Types of VolcanoesComposite Volcano- Alternating layers of

rock caused by alternating types of eruptions

Explosive lays down rocks then covered by lava, Another explosion,More lavaetc. large cone shaped mountain forms

Page 19: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 20: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 21: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 22: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 23: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
Page 24: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Volcano PartsVent- The pipe that the lava flows throughCrater- funnel shaped pit at the top of a

volcanoCaldera- If the walls of the crater collapse

and the crater becomes very large.

Page 25: Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.

Volcano ZonesRing of Fire- all the way around the

Pacific OceanThrough the Mediterranean SeaMid-Atlantic Ridge- Underwater Mountain

range down the middle of the Atlantic Ocean