VOLCANOES

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                                    VOLCANOES


                                    When a volcano erupts hot gases and liquid rock come up to the surface from inside
WORDS
                                    the earth. The material sometimes slides down mountains as lava or is hurled into the
    border = the line that sepa-
    rates two objects               air as ash or small rocks. Volcanoes often destroy the land around them completely.
    chamber = a closed space or     Gases from eruptions can keep sunlight from reaching the earth and darken the sky
    room                            for years. Volcanoes also build up new islands and mountains and make the soil a
    collide = to crash              good place for crops to grow.
    crack = a very small or nar-
    row opening in an object
    crops = a plant like wheat or   WHERE ARE VOLCANOES LOCATED?
    rice that farmers grow and
    use as food                     The earth’s crust is made up of sections or plates. They always move and at places
    crust = the hard outer layer    where they get together they collide or slide on top of each other.
    of the Earth
    edge = border
    erupt = to explode and send
    smoke, rock and fire into the
    sky
    eruption = when a volcano
    explodes
    flow = the slow movement        90% of all volcanoes are located around the edges of the Pacific Ocean. The Pacific
    hurl = throw                    coasts of Asia, North America and South America form a big circle, which is called the
    gigantic = very, very big       Ring of Fire.
    liquid =fluid, like water
                                    Sometimes volcanoes are found in places where plates move away from each other. In
    located = are found
                                    the Atlantic Ocean, for example, a long range of underwater mountains forms the bor-
    mountain range = a group of
                                    der between two plates. Iceland is a gigantic volcanic island that has come up to the
    mountains that form one line
                                    surface from this mountain range.
    plate = one of the many
    sheets of rock that form the    Other volcanoes form in the centre of plates, where magma comes up from deep in-
    surface of the Earth
                                    side the earth and breaks through the crust. Such areas, like the Hawaiian Islands ,
    pressure =force, weight
                                    are called hot spots.
    Ring of Fire = the land
    around the Pacific Ocean
    where plates get together—
    many volcanoes can be           HOW VOLCANOES ARE
    found here                      FORMED
    rise = to come up
                                    Hot liquid rock, called magma, makes up the
    slide = to move smoothly
                                    inner part of the earth. When it rises to the sur-
    over something
                                    face it cools down and sometimes the flow of
    soil =earth, dirt
                                    magma stops in the inner part. In other places,
    spew = to flow out very
    quickly                         magma unites with gas and creates chambers
    surface =the top layer of the   below the surface of the earth. When the gas
    Earth                           pressure gets higher, magma becomes lighter
    unite = to get or join to-      and it spews out of openings, cracks or vents at
    gether                          the surface.
    vent = a round hole through
    which gases, magma or lava
    can get to the surface
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                                        VOLCANOES



WORDS                                   VOLCANIC ERUPTIONS
 base = the lowest part, the bot-       When a volcano erupts three types of material come to the surface: lava, small pieces
 tom
                                        of rock or ash, and gas.
    blow out = explode , erupt
    chamber = a closed space or         Magma that spreads out of a volcano slowly is called lava. It can reach temperatures
    room                                of up to 1,200° C and glows red to white
    cone = a shape that is round at     when it flows. In most cases, lava mixes
    one end and pointed at the
                                        with steam and gas. All types of lava con-
    other
    crater = a round hole in the
                                        tain silicon and oxygen. As lava moves
    ground formed by an explosion       down a volcano’s slope it cools down and
    develop = grow                      becomes harder, creating very rough
    dust= a powder that has very        blocks or rock.
    small bits of dirt
                                        Small pieces of rock erupt from a volcano
    erupt = to explode and send
    smoke, rock and fire into the       when magma is trapped inside and cannot get out. Gas pressure in the magma cham-
    sky                                 bers gets high and suddenly material is blown out and thrown high into the sky.
    eruptions = when a volcano
    explodes                            Often, the pieces of rock are so tiny that they form ash or dust. Strong winds can blow
    flow =run out smoothly              volcanic dust hundreds or thousands of kilometers away from the place of eruption.
    lava = hot liquid rock that flows
    from a volcano
    layer =cover                        TYPES OF VOLCANOES
    magma = the melted rock that        The two most common types of volcanoes are stratovolcanoes and shield volcanoes.
    is below the surface of the Earth
    pressure =force, weight             Stratovolcanoes are formed like a cone. The base is rather flat and they become
    oxygen = a gas that is in the air   steeper towards the peak. A crater usually forms at the top of the volcano. Such volca-
    and that we need to breathe         noes develop when lava and ash come up from the inner part of the earth and build up
    rough blocks = hard blocks with     layers. First, lava spreads over the surface of the volcano , cools down and becomes
    an uneven surface                   hard. Then pressure builds up underneath the layers of lava and ash and other materi-
    silicon =chemical material that
                                        als are blown out. One of the most famous stratovolcanoes is Mount Fuji in Japan.
    is used to make glass, bricks
    and parts for computers
                                                                 crater
    shield =here: the form of the
    volcano that is very flat                                                                                   ash and lava
    slope =mountain side                                                                                           layers
    spread = to move out of
    steam = the gas that water pro-
    duces when you make it very
    hot
    steep =sharp, not flat
    suddenly =unexpectedly, all of a
    sudden, quickly                                            pipes
    surface =top part of the earth
    tiny = very, very small
    trap = if something cannot get
    out
    underneath = below
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                                     VOLCANOES



WORDS                                Shield volcanoes are dome shaped mountains which are flatter than stratovolcanoes
                                     and built of lava flows. They may start on the sea floor and become so large that is-
                                     lands can rise far above sea level. The Hawaiian mountains were formed this way. The
    crater = a round hole in the     islands, which rise about 10,000 meters above the ocean floor, are the world’s most
    ground formed by an explo-
    sion                             massive volcanoes .

    collapse = to fall down very
    quickly
    create = make
    dome-shaped = formed like
    the round roof of a building
    earthquake = when the
    Earth's surface suddenly
    shakes and creates a lot of
    damage
    erupt = to explode and send                                  lava comes out of the inside of
    smoke, rock and fire into the
    sky                                                           the volcano and flows slowly
                                                                        down the slopes
    extinct = something that
    does not exist any more
    flow = the slow movement
    lava = hot liquid rock that
    flows from a volcano
    massive = very, very big
    rise = go up
    scientist =a person who is       Volcanoes also create holes, called craters and cal-
    trained in science               deras. Calderas are larger than craters and are formed
    sea level =the normal height     when parts of the volcano collapse. Sometimes these
    of the sea; it is used for       holes are filled with water and form a lake.
    measuring other heights , like
    the height of a mountain
    shield =here: the form of the
    volcano that is very flat
    sign = a signal that says that   VOLCANIC ACTIVITY
    something will happen            Some volcanoes are active. They erupt very often, like Italy’s Mount Etna, which erupts
    vent = a hole through which      every few years. Inactive volcanoes have not erupted for a long time, but scientists
    gases, magma or lava can         warn that they may become active some day. Extinct volcanoes, like Mount Kenya in
    get to the surface
                                     Africa, will probably never erupt any more.

                                     Volcano experts do their best to warn the population when a volcano may erupt.
                                     Sometimes smaller earthquakes or clouds of gas from vents tell observers that a vol-
                                     cano could erupt soon. Most of the time, however, there are no signs at all.
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                                      VOLCANOES




                    Surtsey, Iceland : In 1963 under-          Vesuvius, Italy : History's most
                    water eruption began forming the           famous eruption in 79 A.D. de-
                    island of Surtsey ; today covers 2.6       stroyed the famous towns of Her-
                    square kilometres                          culaneum and Pompeii



Mt. Saint Helens, USA : Eruption of                                                                             Mauna Loa, Hawaii :
1980 released large amounts of                                          Mt. Etna, Italy : Most active vol-
                                                                                                                World's largest volcano,
rock and hot ash ; killed 57 people                                     cano in Europe ; 20,000 people
                                                                                                                rises 9,100 metes
                                                                        killed in 1669 eruption
                                                                                                                above sea floor.




                       Paracutin, Mexico : Began on a
                       farmer's field in 1943 ; built
                       cylinder cone over 150 metres
                       high in 6 days




                                                                                                        Mt. Pinatubo, Philippines : Erup-
                                                                                                        tion in 1991; spewed 20 million
                                                           Krakatoa, Indonesia : Eruption               tons of gas into the atmosphere
    Cotopaxi, Ecuador : 6,000 m
                                                           of 1883 was heard about
    above sea level ; eruption in
                                                           5,000 km away ; sea waves of
    1877 produced mudflow that
                                                           over 40 m ; 30,000 people
    travelled 240 km ; killed 1,000
                                                           drowned on nearby islands
    people




                   WORDS                                                   very soft and full of water the sides of hills
                                                                           can move down and destroy roads or houses
                      A.D. = after the birth of Christ                     release = to set free
                      covers = has an area of                              rise = to go up
                      cylinder cone =shape that is round on one
                                                                            sea level =the normal height of the sea; it is
                      side and pointed at the end
                                                                            used for measuring other heights , like the
                      drowned = to be killed by water                       height of a mountain
                      eruption = when a volcano explodes
                                                                           spew = throw out
                      mudflow =when it rains and the earth gets
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                                VOLCANOES




    Challenger Deep : is the deepest
    known place in the sea—
                                            trench : a very deep place in
    10,900 metres below sea level.
                                            the ocean
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    VOLCANOES




              Volcanic Eruption




        Mount Saint Helen 1982

				
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