原版英语RAZ 教案(T) Earthquakes, Volcanoes, and Tsunamis.pdf

《原版英语RAZ 教案(T) Earthquakes, Volcanoes, and Tsunamis.pdf》由会员分享，可在线阅读，更多相关《原版英语RAZ 教案(T) Earthquakes, Volcanoes, and Tsunamis.pdf（12页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、www.readinga-LEVELED READER ALEVELED BOOK TWritten by Elizabeth AustinEarthquakes,Volcanoes,and TsunamisQTWVisit www.readinga- for thousands of books and materials.Earthquakes,Volcanoes,and TsunamisA Reading AZ Level T Leveled BookWord Count:1,449Earthquakes,Volcanoes,and TsunamisLevel T Leveled Boo

2、k Learning AZWritten by Elizabeth AustinAll rights reserved.www.readinga-Photo Credits:Front cover,page 4:Photodisc/Getty Images;back cover,title page,pages 7,13(all),14,17,21:ArtToday;page 8:courtesy of Library of Congress,Prints&Photographs Division LC-USZ62-55720;page 9:Boris Grdanoski/AP Images;

3、page 11:StockTrek/Photodisc/GettyImages;page 15:Roger Ressmeyer/Corbis/VCG/Corbis Documentary/Getty Images;page 16:Marshall Myrman/Corbis;page 19:Harry Yeh,University of Washington;page 20:Eric Skitzi/AP ImagesCorrelationLEVEL TP3838Fountas&PinnellReading RecoveryDRAwww.readinga-Earthquakes,Volcanoe

4、s,and TsunamisWritten by Elizabeth AustinEarthquakes,Volcanoes,and Tsunamis Level T 34Table of ContentsIntroduction.4Deep Within the Earth .5Earthquakes:Terrible Trembling.7The Richter Scale.10Volcanoes:Enormous Explosions.11Tsunamis:Wild Waves .16Conclusion .21Glossary .22IntroductionWe usually thi

5、nk of the ground and the ocean as peaceful things.The ground lies quietly beneath our feet,and the ocean laps gently against the shore.But forces deep within the Earth can suddenly destroy that peacefulness.These forces cause violent shakings called earthquakes;explosions of ash,gases,and hot rocks

6、called volcanoes;and huge waves called tsunamis(tsoo-NOM-ees).In this book,you will read about these amazing events and the forces that cause them to happen.Smoke rises from what seems to be a peaceful volcano.Earthquakes,Volcanoes,and Tsunamis Level T 56PacificPlateUnderneath the plates,the Earth i

7、s very hot.It is so hot that rock melts into a liquid called magma.The plates float on top of this liquid magma.The magma is always moving,dragging the plates around with it.At the edges of the moving plates,three different things can happen.If the plates are moving against each other,one plate slid

8、es over or under the other plate(Fig.1).If the plates are moving past each other,the edges of the plates grind together(Fig.2).And if the plates are moving apart,they make a gap where magma seeps out(Fig.3).MountainsMagmaMagmaMagmaFig.1Fig.2Fig.3MountainsDeep Within the EarthBeneath the soil,rock,an

9、d water on the surface of our planet,the Earth is constantly changing.The top layer of Earth is made of giant pieces of rock,like the pieces of a puzzle.The pieces of rock,called plates,make up continents and ocean floors.Where the edges of the plates come together,there are often cracks and gaps,ca

10、lled faults.The dotted lines show the edges of the plates.Tectonic PlatesPacificPlateAustralianPlateIndianPlateEurasianPlateNazcaPlateSouth AmericanPlateNorth AmericanPlateAfricanPlateAntarcticPlateScotia PlateEQUATOREarthquakes,Volcanoes,and Tsunamis Level T 78Earthquakes:Terrible TremblingThe plat

11、es usually move very slowly.But sometimes large pieces of the plates get caught.The plates keep trying to move,but these large blocks of rock hold them back.The pressure and energy build up.Then,suddenly,the rocks give way,releasing all that pressure and energy.The plates jerk forward,and the ground

12、 shakes.Far above,on the surface,people feel an earthquake.Earthquakes can damage or even destroy buildings.In a small earthquake,the ground shakes a little,causing some hanging objects to swing.Tree branches sway,as if there were a gentle breeze.Some earthquakes are so small that we do not notice t

13、hem.But sometimes the shaking is so strong that buildings crumble,bridges collapse,and large cracks open in the ground over large areas.The ground here was ripped open by an earthquake.Earthquakes,Volcanoes,and Tsunamis Level T 910The Richter Scale1 People cannot feel the earthquakeonly sensitive in

14、struments can detect it.2 People usually do not feel it;some people in tall buildings may sense a slight swaying.3 Many people near the origin of the earthquake notice the shaking.No damage occurs.4 People at the origin of the quake definitely feel it.Hanging objects sway.Water sloshes in swimming p

15、ools.Some weak buildings may be damaged.5 Felt over a wider area.Usually lots of damage to weak buildings at and around center.Some damage to strong buildings.6 Lots of damage to weak buildings;some damage to strong buildings.Damage can spread over 160 kilometers(100 mi).7 A very major earthquake.Mo

16、st buildings at the center are destroyed.Cracks form in the Earth.Underground pipes break.Large landslides can occur.8 Buildings and bridges destroyed.Large cracks appear in the ground.Large landslides.9 The ground appears to move in“waves.”Entire rivers may move.Objects can be thrown into the air.T

17、otal destruction of buildings and other structures.There is no top to the Richter scale,but the strongest earthquake ever recorded was a 9.5.We measure the strength of earthquakes on an instrument called a seismograph(SIZE-moh-graf).Each earthquake is given a number from the Richter(RICK-ter)scale d

18、epending on its strength.You can look at the chart on the next page to learn what the different strengths of earthquakes feel like.For each number on the Richter scale,an earthquake is ten times as strong as the previous number.A 6.0 earthquake is ten times as strong as a 5.0 earthquake.It is one hu

19、ndred times as strong as a 4.0 earthquake!The largest earthquake ever recorded measured 9.5 on the Richter scale.It occurred on the coast of the South American country of Chile.Scientists are still learning about these dangerous events.One day,they may be able to warn people before earthquakes occur

20、.A seismographEarthquakes,Volcanoes,and Tsunamis Level T 1112Volcanoes:Enormous ExplosionsA volcano occurs wherever magma from deep inside the Earth comes out through a crack in the surface.Volcanoes usually happen near the edges of the plates,where there are many cracks and thin spots where the mag

21、ma can leak out.When the magma pours onto the surface,it hardens,often piling up into a mountain.Sometimes,the liquid rock flows peacefully out across the land.This is how many of the active volcanoes on the Hawaiian Islands behave.Runny liquid rock on this Hawaiian volcano flows smoothly,like a pea

22、ceful river.But sometimes,the hot magma cools before it gets to the surface.It hardens into a solid piece of rock,plugging up the crack or hole where it had been seeping out.It acts like a plug in a bottle.The magma continues to push upward.Hot gases in the magma press against the plug.The pressure

23、gets greater and greater.Suddenly,the volcano explodes.Huge chunks of rock burst from the volcano.Entire mountainsides can be ripped away.Hot,poisonous gas,ash,and melted rock shoot into the sky.The volcano erupts with unbelievable power.Some volcanoes become plugged(left),and then they explode viol

24、ently(right).MagmaDust,ash,and gasLavaflowPlugEarthquakes,Volcanoes,and Tsunamis Level T 1314A volcano can cause an explosion of extremely hot,poisonous gases.The explosion can be so powerful that it knocks over entire forests,and so hot that it starts destructive fires.Some large volcanoes have sno

25、w and ice on top.The hot gases melt all the snow and ice at once,and the water rushes down the mountain.This large,dirt-filled flood is called a mudslide.A mudslide is like a liquid landslide.These trees were blown over by the explosion of Mount St.Helens.Many dangerous and destructive things happen

26、 during volcanic eruptions.When mountains explode,they send tons of rock rolling down their sides.These falling rocks are called landslides.Landslides can bury whole cities.They can block rivers,causing floods.Clouds of ash and dust rise into the air during volcanic eruptions.The ash falls to the gr

27、ound like snow.The ash is so heavy that the roofs of houses can collapse under its weight.An ash cloud can spread all around the world.Large ash clouds can even block out sunlight.The temperature of the entire Earth can cool down after a large volcanic eruption.Mount St.Helens after it eruptedMount

28、St.Helens,in Washington State,before it erupted in 1980Earthquakes,Volcanoes,and Tsunamis Level T 1516Scientists are not yet able to predict when earthquakes will happen.But fortunately they have gotten very good at predicting when a large volcano is about to erupt.In 1991,scientists warned the peop

29、le living around a volcano in the country of the Philippines that the volcano was about to erupt.Many people left the area and found safety before the huge volcano erupted.Scientists gather information from a volcanic fissure.Tsunamis:Wild WavesTsunamis are huge waves caused by earthquakes or volcan

30、oes.They used to be called“tidal waves.”But the word“tidal”means something to do with the oceans normal tides,and tsunamis have nothing to do with the tides.Tsunamis can be as high as a football field is long.They are the largest waves in the world.Tsunamis are the largest waves in the world.Earthqu

31、akes,Volcanoes,and Tsunamis Level T 1718The edges of the plates,where earthquakes and volcanoes often occur,usually lie near the edges of the oceans.The shaking of an earthquake or the explosion of a volcano can cause large landslides.Entire hills can collapse,and sometimes they fall into the sea an

32、d make huge waves.Earthquakes and volcanoes can also be found under the sea.Underwater earthquakes cause the sea floor to move violently.Undersea volcanoes cause explosions under the water.Both of these events create huge waves that spread across the surface of the ocean.Steam rises from a volcano n

33、ear the sea.Tsunamis speed outward away from their source in all directions.A tsunami can cross an entire ocean.Tsunamis travel extremely fastup to 320 kilometers per hour(200 mph).In the open ocean,tsunamis may not be very high above the surface of the water,but they are very deep.As tsunamis appro

34、ach land and move into shallow water,the elevated ocean floor pushes the wave upward.The wave slows to about 70 kilometers per hour(45 mph),but the ocean floor lifts it higher and higher.By the time a tsunami reaches land,it is tall enough to destroy almost anything in its path.When tsunamis approac

35、h the shore,they break as giant waves.Tsunami near shoreShoreWhen a Tsunami Wave Reaches ShoreTsunami in open ocean with most of the wave below the surface10 to 100 feet highEarthquakes,Volcanoes,and Tsunamis Level T 1920The largest tsunami ever recorded happened when an earthquake caused a landslid

36、e along the coast of Alaska.But this wave was in a very small bay,only a short distance from the landslide that caused it.Most tsunamis are between one and ten stories high when they reach the shore.That might not sound very high,but it is hard to imagine the power of this much moving water.Most coa

37、stal towns and villages are much less than 30 meters(100 ft)above the sea.Even a small tsunami can destroy houses,streets,and entire towns.A tsunami caused by a volcano in Indonesia killed 36,000 people in 1883.Damage from a tsunamiLike volcanoes,tsunamis are becoming easier to predict.They usually

38、do not hit the shore until a few minutes to a few hours after the earthquake or volcano that causes them.Scientists have instruments that detect volcanoes and earthquakes.When a large one happens,scientists have time to warn people that a tsunami may be coming.Unfortunately,the system cannot warn pe

39、ople in time to save their homes or belongings.But they do have time to save their lives,which is the most important thing.Many people describe tsunamis as“walls of water.”Earthquakes,Volcanoes,and Tsunamis Level T 2122Glossaryearthquake(n.)the shaking of Earths crust caused by underground vibration

40、s(p.4)faults(n.)cracks in Earths crust along which movement occurs(p.5)landslides(n.)moving masses of soil and rock that flow down slopes(p.13)magma(n.)melted,liquid rock beneath the Earths surface(p.6)mudslide(n.)a dirt-and debris-filled flood of water(p.14)plates(n.)large sheets of rock that make

41、up the Earths crust(p.5)Richter scale(n.)the scale that measures the strength of earthquakes(p.9)tsunamis(n.)enormous ocean waves caused by underwater,earthquakes,landslides,or volcanoes(p.4)volcanoes(n.)places on the Earths surface where gases,ash,and lava spew onto the surface(p.4)ConclusionOur qu

42、iet planet occasionally turns violent.During a large earthquake,the ground shakes,destroying homes and property.In an explosive volcanic eruption,liquid rock,poisonous gases,ash,and landslides can bury cities.And tsunamis can cause billions of dollars in damage along coastlines.Scientists are trying to learn as much as they can about these violent events.As they learn more,scientists can predict volcanoes,earthquakes,and tsunamis in order to save thousands of lives.An earthquake destroyed this building.