Chapter 2 Earthquakes and Volcanoes

Chapter 2 focuses on Earthquakes and Volcanoes.

Lessons included in this chapter:

#4 Earthquakes - The Rolling Earth

#5 Volcanoes

#6 Volcanic Terms

Resources for Teachers can be found under the Chapter #2 Copymaster.

Select from the options on the right to proceed.

Earthquakes - The Rolling Earth Lesson #4

rollingearth1

 

An earthquake is a sudden, rapid shaking of the Earth caused by the release of energy stored in rocks. This energy can be built up and stored for many years and then released in seconds or minutes. Many earthquakes are so small that they can not be felt by humans. Some, on the other hand, have caused great destruction and have killed hundreds of thousands of people. The pink lines and dots on the map of the world above indicate the regions of earthquake activity.

 

There are two major regions of earthquake activity. One is the circum-Pacific belt which encircles the Pacific Ocean, and the other is the Alpide belt which slices through Europe and Asia. The circum-Pacific belt includes the West coasts of North America and South America, Japan, and the Phillipines.

Over one million earthquakes may occur each year on the Earth. Most earthquakes last only seconds, but some large quakes may last minutes. About 90% of all Earthquakes are produced at plate boundaries where two plates are colliding, spreading apart, or sliding past each other. When these plates move suddenly they release an incredible amount of energy that is changed into wave movement. Earthquake waves resemble sound and water waves in the manor in which they move. It is these waves that roll through the Earth's crust causing buildings to collapse, bridges to snap, mountains to rise, the ground to fall, and in some cases the ground to open up into huge cracks.

 

rollingearth2 


Why do earthquakes occur? Scientists believed that the movement of the Earth's plates bends and squeezes the rocks at the edges of the plates. Sometimes this bending and squeezing puts great pressure on the rocks. Rocks are somewhat elastic, they can be bent without breaking. Have you ever stretched a rubberband? You know if you increase the tension too much though, the rubberband will snap!! Rock layers act somewhat the same way, if the pressures becomes too great the rock layer will break and move. When this occurs the layers will move along a crack in the Earth's crust called a fault or the release of energy will cause a new faultline to be produced. This rupture of the rocks and the resulting movement causes an earthquake.

 

rollingearth3 


This is an aerial photo of the San Andreas fault line in California. The red arrows point to the crack in the crust that is the surface fault. This fault is the boundary between two huge plates, the North American plate and the Pacific plate. The two plates are sliding past each other in opposite directions. This type of plate boundary is called a transverse boundary. A transverse boundary is actually a tear in the Earth's crust. The black arrows represent the directions that the two plates are traveling.

This fault line is perhaps the most studied transverse boundary in the world. Many earthquakes each year occur on the San Andreas fault which runs in California from the Mexico border east of San Diego north to the San Francisco Bay area. The next photo shows the destruction that occurred during the 1971 San Fernando earthquake.

 

rollingearth4


This aerial photograph shows the destruction that occurred during the February 2, 1971 San Fernando earthquake. The freeway bridge and road were extensively damaged during this shaking of the crust.

 

rollingearth5 


When an earthquake occurs an area of the crust will move very suddenly and with a great release of energy. The point of the actual rock rupture is called the focus . The focus is usually found far beneath the surface. The point directly above the focus on the surface of the Earth is called the epicenter.

When the rocks move suddenly they will produce waves in the Earth's crust. These waves move out in all directions and can produce widespread damage on the Earth's surface.

When the rupture of the rock occurs the release of energy causes seismic waves to be produced. Just as wind energy causes waves in water to move across a lake or ocean, seismic waves move through the layers of the Earth. These seismic waves are what produces the destruction that can accompany an earthquake by heaving, shaking, and cracking the ground as they pass through an area. The seismic waves spread out in all directions from the focus.

 

rollingearth6

 

Compression waves are one type of seismic wave. They are the first to arrive at the surface of the Earth. Because of this they are given another name, P or Primary waves.

P waves are the fastest of the seismic waves. They travel at incredible speeds, 14,000 m.p.h at the surface to over 25,000 m.p.h. through the core of the Earth. P waves are even able to pass all the way through the entire Earth.

When P waves strike an object they push and pull the object , like a train engine bumping into a railroad car which then bumps into another and so on all the way through the whole length of the train. This jackhammer movement is the first sign that an earthquake is occurring.

As a wave passes through a house, the house is pushed and pulled. If the house is not strong enough it might collapse.

 

rollingearth7


Shear waves reach the surface shortly after the P waves and are given the name S or Secondary waves. S waves travel at about half the speed of P waves. They move objects in their paths in an up and down motion in the direction that the wave is moving.

S waves can only move through solids and because of this can travel only through the crust and mantle of the Earth. When S waves strike the outer core, which is made of liquid iron and nickel, the waves stop.

 

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Surface waves are the third type of wave. These are the waves that produce the most destruction. They originate from the arrival of P and S waves at the surface. They are much slower than both P and S waves. Surface waves are limited to travel along only the surface of the Earth, just as waves in a body of water are limited to travel along only the surface of the water.

There are two types of surface waves: Love waves and Rayleigh waves. Love waves move in a manner very similar to S waves but the movement to objects in it's path is side to side instead of up and down. Rayleigh waves travel much in the same way as waves in water. Rayleigh waves have an almost circular pattern to its wave motion.

 

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The Richter Magnitude is a number that is used to measure the size of an earthquake. The magnitude is a measure of the strength of the seismic waves that have been sent out from the focus. A scientist uses a seismograph to determine the strength of the earthquake. A seismograph is an instrument that measures the amount of ground motion that an earthquake produces.

Each number on the Richter Scale represents an earthquake that is ten times as powerful as the number below it.

Examples: An earthquake measuring 6 is ten times stronger than a magnitude 5 quake. An earthquake of a magnitude 9 is 10,000 times more powerful than a 5.

The strongest earthquake ever measured was a 8.9 off of the coast of Ecuador in 1906. Earthquakes of 6 and above are considered major quakes. Earthquakes of 7 and above have the ability to do great damage and kill many people.

 

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Each of the graphs on this page shows an earthquake reading on a seismograph. The waves from an earthquake sets a writing device in motion showing the magnitude and the length of time that the earth is in motion during a quake.

The strength or magnitude is recorded in the verical (up and down) lines. The stronger the quake the longer the lines will be drawn on the graph.

The duration (length of time) that a quake occurs is represented in the horizontal lines. The duration of the earthquake in the top graph shows a quake lasting about 40 seconds. Each box on the graph is a one minute time duration. The bottom earthquake lasted about one minute and 20 seconds.

Which earthquake was stronger??

 

Write your answers to the questions below in complete sentences on a piece of paper. Use the page titles directly under the questions to move through the lesson to find the answers for the questions. When you are finished click on the Earth icon so that the next group can begin the lesson.

1. How are earthquake waves produced?

2. What does a Richter Scale show?

3. What are the differences between compression, shear, and surface waves?

Volcanoes Lesson #5

Volcanic activity is the most powerful force in nature. Some volcanic eruptions are much more powerful than the largest nuclear explosion. Volcanoes have killed thousands of people and have created some of the most frightening events in human history.

Volcanoes have been the basis for myths and legends the world over.

Volcanoes are also responsible for much of the land we live on, 90% of all the continents and ocean basins are the product of volcanism. The air we breathe, and the water we drink have been produced by millions of years of eruptions of steam and other gases.

 

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The volcanic mountain above is Mount Adams which is located in the Cascade Range of Washington.

 

The word volcano is derived from the name of the ancient Roman island of Vulcano which lies off the southwest coast of Italy. The Romans believed that Vulcan, the god of fire and the maker of weapons, used the volcano on that island to forge his weapons.

Volcanoes are not alive but scientists use human terms to talk about volcanoes, such as active, alive, dormant, resting, sleeping, extinct, dead, lifetime, and restless.

 

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The island in the middle of the picture is Vulcano. The island was formed by Vulcanian eruptions, which are eruptions of hot gas and steam followed by ejections of thick and pasty lava.

 

The term Volcano has two definitions;

1. An opening in the crust of the Earth in which molten rock called magma and gases can escape to the surface.

2. The mountain that is formed from volcanic eruptions.

 

volcanoes3

 

This is a photo of the volcano Paricutin (Pear-A-Koo-Teen). Paricutin's cone formed from nine years of almost constant eruptions. Red hot cinders exploded from the main vent and landed near it building the cone higher and higher. This type of cone is called a cinder cone. You will learn more about the types of volcanic cones in the eighth lesson, "Volcanic Cones and Eruptions".

 

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Volcanoes actually build themselves into a mountain with repeated eruptions. In 1943 a farmer in Mexico noticed that some cracks (fissures) in his corn field were growing wider and wider. The next day his field was engulfed by a growing volcanic cone (Light Green). During the week the cone grew 500 feet taller (Dark Green). Within a year (Dark Gray) Paricutin was over 1200 feet higher than the surrounding landscape. During the next eight years the volcano did not grow much taller but the cone's base grew wider and wider (Light gray). Paricutin stopped erupting in 1952 almost as fast as it started. The mountain has been silent since.

Volcanoes can build themselves into high mountains one day and in the case of Mt. St. Helens erupt violently blowing their top off the next day. Mt. St. Helens lost over 1300 feet of its summit during the eruption and simultaneous landslide of 1980.

 

Volcanoes are classified as active, dormant, and extinct. Active volcanoes are either currently erupting or have erupted in recorded history. There are over 500 volcanoes on Earth that fit this category today. Dormant or resting volcanoes are not currently erupting but are considered likely to do so. Mt. St. Helens had been dormant for one hundred twenty-three years before it erupted in 1980. Extinct or dead volcanoes have not erupted in recorded history and are not expected to erupt again.

 

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The photo above is of beautiful Mt. St. Helens before it erupted on May 18, 1980. Mt. St. Helens was one of the most beautifully symetrical stratovolcanoes in the world. It was called "the Fuji of the west". Mount Fuji, in Japan, is the most photographed mountain in the world. The next card will show you what this mountain looked like shortly after the eruption. The lake in the foreground changed. The lake's level is now 150 feet higher because the landslide and eruption filled the bottom of the lake with rock, soil, and pyroclasts.

 

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This is Mt. St. Helens four months after the eruption. Notice the loss of over 1300 feet of the summit. Also notice the total devastation of the beautiful forests and how Spirit Lake rose. Spirit Lake's surface was completely filled with trees that were blasted into the lake by the force of the eruption. The lake is now much more shallow, wider, and longer than before the eruption. Huge trees still float across the lake today.

 

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The eruption left a crater over a mile wide and over 2000 feet deep. The mountain is still active today spewing small whisps of steam. A lava dome is growing in the bottom of the huge crater.


A lava dome is a steep mass of very thick and pasty lava that is pushed up from the main vent. The lava is so viscous (thick and pasty) that it does not flow but slowly rises higher with each movement of magma in the conduit. Think of toothpaste that is slowly squeezed and then stopped and then squeezed again from the tube. This is how the lava dome in Mt. St. Helen's was formed.

The dome's exterior surface is very rough with chunks of lava that were formed from small eruptions that broke the cooled and hardened surface into blocks.

 

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The dome slowly "grew" larger and larger over a seven year period. An earlier dome started to form one month after the famous eruption when very thick lava (dacitic lava) rose into the crater from the magma chamber below. This dome was destroyed by an explosive eruption just a month later.

The large dome that is very visible today is over 900 feet tall (taller than an 80 story building) and over 3000 feet wide (10 football fields). As large as the lava dome is, it is still dwarfed by the huge crater that was the result of the 1980 eruption. Steamy whisps of steam are still visible from the dome telling us that the volcano's magma is filling the conduit, making the volcano still active today.

 

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There are three ways that volcanoes form. Subduction Zone volcanoes form at the boundaries of two plates, one overriding the other. Subduction zone volcanoes are the most violent and destructive of the volcanic types. Mt. St. Helens, Mt. Pinatubo, Krakatoa, and Mt. Vesuvius are all famous explosive subduction zone volcanoes. Mid-ocean rift volcanoes form where two oceanic plates are spreading apart. There are more rift zone volcanoes than any other type.

These mid-ocean or rift zone volcanoes are the world's longest continuous mountain chain. This mountain chain encircles the entire Earth. It is more than 40,000 miles long.

The third way that volcanoes form occurs at a Hot Spot. Hot spots are usually found under oceanic crust, but can be located under continental crust. You will learn more about Hot Spot volcanoes in the lesson "Hot Spots-Yellowstone and Hawaii".

The diagram above shows the three ways that volcanoes form.

 

Predicting exactly when a volcano will erupt is next to impossible. Today geologists are becoming much more accurate in making the public aware that a volcano is showing signs that it may erupt in the near future.

In the months before Mt. St. Helens erupted geologists knew the mountain was getting restless. A magnitude 4.1 earthquake was recorded on March 20 (about 2 months before the large eruption). Many shallow earthquakes were recorded over the next seven weeks. Magma moving higher and higher inside the mountain was causing these earthquakes. As the magma rose it formed a large bulge on the north flank. This bulge was growing daily and the geologists knew that an eruption was soon to be.

What the authorities did was evacutate most of the people in and near the mountain. Some decided to stay. Almost everyone that was near the eruption was instantly killed. In all, 57 people died. Without the evacuation perhaps as many as 30,000 deaths would have been attributed to Mt. St. Helens fury.

 

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The geologists in the photo are measuring a growing fissure near the lava dome in Mt. St. Helens crater. As magma rises the fissure will grow wider telling the geologists that the magma is rising again.

Scientists can not stop a volcano from erupting but with constant monitoring they can warn and evacuate people and save lives.

 

Many volcanoes erupt in very consistant patterns, while other volcanoes have no eruption pattern at all. This makes forecasting eruptions difficult.

What makes predicting eruptions even more difficult is the fact that many volcanoes start with one type of eruption pattern and then change eruption patterns as they grow older.

Some of the most powerful eruptions in recorded time have come from volcanoes that have been dormant for hundreds and even thousands of years.

 

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Here we have geologists studying a tilt meter. A tilt meter is used to measure the growth of the lavadome in the foreground. The tiltmeter will show a different angle as the dome grows. With careful study the geologists can tell if magma is on the rise and that an eruption may occur in the near future.

 

Write your answers to the following questions on a sheet of paper. Click on the Earth icon after you have finished to allow the next group to begin the lesson. You can click on page titles located directly under the questions to go back into the lesson to find the answers.

 

1. At what type of plate boundaries do volcanoes form?

 

2. What are the two definitions for the term volcano.

 

3. Write definitions in your own word for the following terms:

a) Active Volcano

b) Dormant Volcano

c) Extinct Volcano

Volcanic Terms Lesson #6

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The volcanic mountain in this picture is Mayo Volcano on the island of Luzon in the Philippines. Mayon is a beautiful example of a stratovolcano.

 

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This is a model of the interior and exterior of a stratovolcano. The letters represent important terms that you need to know to understand how volcanoes are formed and how they work.

 

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The letter A represents a magma chamber. Magma is molten rock that is located under the surface of the Earth. A magma chamber is usually located far beneath the surface of the Earth where an oceanic plate is driven down into the mantle by a continental plate. The oceanic plate melts as it desends into the upper layer of the mantle. Some ocean water gets trapped with the oceanic plate and is turned into steam by the intense heat.

The magma is less dense and under extreme pressures that force it up toward the surface. This molten rock and gas collects in a magma chamber until it can escape to the surface.

 

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The letter B represents a Dike. Stratovolcanoes are built by many alternating eruptions of lava and ash. The magma below and inside the mountain exerts a lot of pressure on the crust and on the volcano itself. The magma pushes its way through small cracks in the crust and finally reaches the surface. This causes a dike to be produced.

A dike is an intrusion of magma that cuts through layers of already existing rock.

 

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The letter C represents a Side vent. When the magma reaches the surface of the Earth it is then called lava. The lava leaving the side vent causes the volcano to add a layer of lava and usually a layer of ash with each eruption. These eruptions build the volcano higher and wider. Hawaii has volcanoes with many side vents that have built the islands with very wide bases. Some volcanoes on the other hand have few or no side vents. The materials that makes up the magma (gases, minerals, steam) determines how the magma will arrive at the surface. You will learn more about magma and lava in the next lesson "Lava Flows and Pyroclasts".

 

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The letter D represents a conduit. A conduit is the main tube or pathway for the magma to reach the surface.

Devils Tower in Wyoming is an example of a cooled and hardened conduit.

 

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This is a photo of Devils Tower National Monument. Devils Tower in Wyoming is an ancient conduit. The source for the magma moved and the magma in the conduit cooled and hardened into a very hard lava rock called basalt. The volcanic cone was made of softer volcanic materials probably ash and pumice that slowly eroded away leaving only the conduit standing. Today we know this ancient conduit as Devils Tower National Monument.

 

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The letter E represents the crater and main vent of a volcano. The crater is the bowl shaped opening located at the top of the volcano. The crater is also the steep sided walls made of hardened lava that surround the main vent. Lava can flow from the main vent, but not all volcanoes eject large amounts of lava. Some volcanoes explode molten rock and huge amounts of gas from the main vent.

Volcanoes are not always erupting and the crater may be a bubbling caldron of lava without enough pressure to erupt.

 

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This photograph is of a volcanic cone. The crater is located at the top. The side vent is active and a lava flow is running down the side of the cone. A fissure is bringing the magma to the side vent. This photo is courtesy of Dr. Scott Rowland of the University of Hawaii.

 

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You are looking at the inside of a volcanic crater. The steep walls were produced be many eruptions ejecting very liquid lava. This lava then lands on the crater walls building them higher and higher. The lava in the main vent is extremely hot (probably about 1800 degrees F.) The lava on top cools and hardens because the air that it is in contact with is so much cooler than the lava. This hardened lava will then be dragged back down under the surface and remelted. You probably noticed the same process if you have ever heated soup on the stove. If you did not keep stirring the soup it formed a "scum" on top.

 

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The letter F represents layers of tuff and lava. When a volcano erupts it may eject lava, lava rock and ash. When stratovolcanoes are built some of the lava and ash lands and stays on the volcano building it higher and higher with each eruption. The ash hardens into a rock that is called tuff.

 

Write your answers to the following questions on a sheet of paper. 

 

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Label the following parts of a volcano by writing your answers on a sheet of paper.

 

A.

 

B.

 

C.

 

D.

 

E.

 

F.

 

Chapter 2 Copymaster: Test, Reviews, Answer Keys, Chapter Schedule

Chapter #2 Copymaster includes tests and answers for students and teachers on material covered in Chapter 2.

Select options on the right hand side to proceed. 

Baseball Game

Materials:


  • One die
  • One baseball diamond transparency
  • Four markers for the runners


Instructions

Break your class into two teams.
Ask a student a question. If they answer correctly award them the base that they rolled with the die. (See rules below) If they answer incorrectly their team is out. One out per inning.

Rules for the game


  1. Shake the die 
    1. single
    2. double
    3. triple
    4. home run
    5. single
    6. single

  2. Ask the question-If they answer correctly award them the base that they rolled with the die. Place a marker on the base that they earned. If there is a runner on base ahead of them move the runner the same amount of bases as the batter. If they answer incorrectly their team is out. One out per inning.

  3. Keep rolling and asking questions until a player answers incorrectly. When they answer incorrectly switch batting teams.

Chapter 2 Review

Chapter Review 

Chapter 2
Earthquakes and Volcanoes


  1. What is a Tsunami?




  2. Explain the difference between a focus and an epicenter.




  3. Name the three types of earthquake waves.




  4. What is magnitude and how is it related to the Richter Scale?




  5. What is an fault?




  6. What are the two definitions for a volcano?




  7. What is the difference between active, dormant, and extinct volcanoes.

  8. What is the difference between magma and lava?




  9. Label the following diagram




    A._____

    B._____

    C._____

    D._____

    E._____

    F._____

  10. Name and describe the 3 ways that volcanoes form.






  11. What causes earthquakes to occur?




  12. Where do the majority of earthquakes occur?




  13. What causes volcanoes to grow larger?




Chapter 2 Review Answer Key

Chapter Review 

Chapter 2
Earthquakes and Volcanoes


  • What is a Tsunami? A seismic seawave produced by a volcanic eruption, an underwater landslide, or an earthquake. They sometimes reach heights of over 50 feet. They are also called tidal waves. 

  • Explain the difference between a focus and an epicenter. The focus is the actual point of rock breakage or movement. the focus is usually located far below the surface of the Earth. The epicenter is the point on the surface of the Earth directly above the focus.

  • Name the three types of earthquake waves. Compression or P waves, Shear or S waves, and Surface waves.

  • What is magnitude and how is it related to the Richter Scale?
    Magnitude is the measure of the strength of the seismic waves that have been sent out from the focus. Richter scale is a number used to measure the strength of an earthquake. A Richter scale measurement of 1-5 is of low intesity and 6-9 is of high intensity.

  • What is an fault? A long crack in the Earth's crust. Earthquakes occur along such cracks.

  • What are the two definitions for a volcano? 1) An opening in the Earth's crust in which molten rock and gases can escape. 2) The mountain built by repeated eruptions of lava, or pyroclasts or, both lava and pyroclasts. 

  • What is the difference between active, dormant, and extinct volcanoes. Active volcanoes are either currently erupting or have erupted in recorded history. Dormant volcanoes are not currently erupting but are considered likely to do so. Extinct volcanoes have not erupted in current history and are not considered likey to do so.

  • What is the difference between magma and lava? Magma is molten rock under the Earth's surface. Lava is molten rock on the Earth's surface.

  • Label the following diagram

    A. Magma chamber

    B. Dike

    C. Side vent

    D. Conduit

    E. Crater

    F. Layers of lava and ash



  • Name and describe the 3 ways that volcanoes form.
    1. Volcanoes can form at subduction zones where two plates collide, one being driven down into the mantle and the other riding over the top. This causes the lithospheric plate to melt and being less dense than the rock in the mantle it will rise. This rising magma will produce a volcano.
    2. Volcanoes can form at a mid-ocean ridge. When the two plates separate magma fills the void and a volcano is produced. These chains of volcanic mountains are the longest mountain chain in the world.  
    3. Volcanoes can also form at a hot spot.


  • What causes earthquakes to occur? 
    Earthquakes occur because the Earth's plate are in motion. The plates do not move smoothly and evenly. Great stresses build up along the plate boundaries. When a plate moves suddenly a great amount of energy is released in the form of wave energy. These waves are what cause the damage from an earthquake.

  • Where do the majority of earthquakes occur?  
    Along plate boundaries. The main earthquake zones are the Circum-Pacific belt that stretches around the rim of the Pacific Ocean and the Alpide Belt in Europe and Asia.


  • What causes volcanoes to grow larger?  
    Volcanoes grow larger from their eruptions. When avolcano erupts it ejects lava, or pyroclasts, or both that builds the cone larger and larger.


  • Chapter 2 Student Vocabulary

    Vocabulary Chapter 2
    Earthquakes and Volcanoes

    Name____________________


    Lesson 4- Earthquakes

    1. Earthquake-



    2. Earthquake belts-
      • Circum-Pacific belt-


      • Alpide belt-


      • Fault-



    3. Focus-



    4. Epicenter-



    5. Earthquake Waves-
      • Compression-



      • Shear-



      • Surface-



    6. Magnitude-


      Lesson 4 continued
    7. Richter Scale-



    8. Seismograph-



    9. Strike-slip Fault/ San Andreas Fault



    10. Tsunami-





      Lesson 5
    11. 2 definitions of volcano- 







    12. Paricutin-



    13. Active Volcano-


    14. Dormant Volcano-

    15. Extinct Volcano-



    16. Lava Dome-



    17. Viscous-



    18. 3 ways that volcanoes form 1. Subduction Zone Volcanoes-



      1. Rift Zone Volcanoes-



      2. Hot Spot Volcanoes-



    19. Tilt Meter-





      Lesson 6
    20. Magma-


    21. Magma Chamber-


    22. Fissure-

    23. Dike-



    24. Side Vent-



    25. Lava-



    26. Conduit-



    27. Main Vent-



    28. Crater-



    29. Tuff- 

    Chapter 2 Teacher Vocabulary

    Vocabulary Chapter 2
    Earthquakes and Volcanoes

    Name____________________


    Lesson 4- Earthquakes

    1. Earthquake- 
      A sudden movement of the Earth's plates that can cause destruction. Earthquakes occur at plate boundaries when built up pressures in rocks suddenly release causing the plates to move along a fault line.

    2. Earthquake belts-
      A) Circum-Pacific belt-Encircles the outer rim of the Pacific Ocean. This area is the most active for earthquakes and volcanoes in the world.

      B) Alpide belt-
      This earthquake belt runs from Western Europe to Central Asia.

    3. Fault-
      A long crack in the Earth's crust.

    4. Focus-
      The place in the Earth's crust where an earthquake occurs. This is usually found deep under the surface of the Earth.

    5. Epicenter-
      The place on the Earth's surface directly above the focus.

    6. Earthquake Waves-
      Also called seismic waves. They are caused by the rapid release of energy caused by movements in the Earth's crust.

      A) Compression waves-
      First and fastest waves produced in an earthquake. They are also called P (Primary) waves. They move in a jackhammer motion.

      B) Shear waves- 
      Second waves to strike an area. Also called S (Secondary) waves. They travel slower than P waves. They move in an up and down roller coaster motion. 

      Lesson 4 continued

      C) Surface waves-
      These are the last waves to strike an area. They are the slowest waves and are confined to the surface of the Earth. They produce the most damage to man made materials. There are two kinds of surface waves; 1. Love waves and Rayleigh Waves.

    7. Magnitude-
      Measurement of the intensity of an earthquake.

    8. Richter Scale-
      Scale used to identify the strength of an earthquake. Richter scale runs from 1-9. Earthquakes with a 6 or above rating are considered powerful.

    9. Seismograph-
      A graph showing the length and severity of an earthquake.

    10. Strike-
      slip Fault/ San Andreas Fault-A strike-slip fault is located at a transverse plate boundary. The two plates slide by each other moving in opposite directions. 

    11. Tsunami
      A very large wave produced from earthquakes, volcanic activity, or an under water landslide. These waves produce 30-100 foot high crests as they break onto the shoreline. They can produce enormous damage to seaside communities.


      Lesson 5
    12. 2 definitions of volcano- 
      1. An opening in the surface of the Earth that allows lava, gas, 
        and pyroclastic material to reach the surface.

      2. The mountain built by repeated eruptions of a volcano. 

    13. Paricutin-
      A volcano in Mexico. This volcano was produced in a farmers field in 1943 and built a 1300 foot cinder cone over 9 years. The volcano was name for the village that was destroyed by a large lava flow from its namesake.

    14. Active Volcano-
      A volcano that is currently erupting or has erupted in recorded time.

    15. Dormant Volcano-
      A volcano that is not erupting currently but has erupted in recorded time and is considered likely to do so again.

    16. Extinct Volcano-
      A volcano that has not erupted in recorded time and is not considered likely to do so.

    17. Lava Dome-
      A lava dome is a steep mass of very thick and pasty lava that is pushed up from the main vent.

    18. Viscosity-
      The thickness of lava and magma determine how the volcano will erupt, what type of lava flow will be formed, and what type of volcanic cone will form. Viscosity is the measure of how thick or thin the lava is. Thick magma or lava is said to have a high viscosity, while thin lava or magma is said to have low viscosity.

    19. 3 ways that volcanoes form 
      1. Subduction Zone Volcanoes-Form where two plate meet, one being driven down into the mantle. These are the most explosive volcanoes because as the plate is driven into the mantle ocean water is mixed into the magma causing the production of steam which makes the magma more explosive.

      2. Rift Zone Volcanoes-These are formed where two plates are separating, magma fills the void left by the divergent plates. These volcanic mountains form a chain that circles the Earth. It is the longest continuous mountain chain in the world, over 40,000 miles long.

      3. Hot Spot Volcanoes-They form where there is a upward flow of very hot solid rock coming from great depths in the mantle. The Hawaiian Islands and Yellowstone Caldera were formed from a volcanic hot spot as the plates moved over that particular hot spot. 

    20. Tilt Meter-
      Tool that measures the amount of change in the slope of a volcano or a lava dome. It is used to help predict an upcoming eruption. The movement of magma in a volcano is a sign that an eruption may be near.





      Lesson 6
    21. Magma-
      Molten rock under the surface of the Earth.

    22. Magma Chamber-
      A large mass of magma usually located far under the surface of the Earth.  

    23. Fissure-
      A long crack in the surface of the Earth that allows magma and gases to reach the surface.

    24. Dike-
      An intrusion of magma that becomes a passageway for magma. This passageway connects the conduit to the side vent. A dike runs through already existing layers of rock.

    25. Side Vent-
      A secondary opening in a volcano that allows magma to reach the surface of the Earth. It is usually located on the flanks of a volcanic cone.

    26. Lava-
      Molten rock that has reached the surface of the Earth.

    27. Conduit-
      The main passage for magma.

    28. Main Vent- 
      The main opening in a volcano. Located at the top of the conduit.

    29. Crater-
      The steep walled bowl shaped opening surrounding the main vent. This steep walled structure is formed by repeated eruptions of ash and lava.

    30. Tuff-
      The rock that is formed by the mixture of lava and ash. This is the rock that is formed on the sides of stratovolcanoes.

    Chapter 2 Test

    Test Chapter 2
    Earthquakes and Volcanoes

    Name____________________

      1. _____ Fault  A. gods and goddesses of ancient mythology
      2. _____Focus  B. Exact point of origin of an earthquake. Usually found deep under the surface of the Earth.
      3. _____ Magnitude  C. The point on the surface of the Earth directly above the earthquake.
      4. _____ Tsunami  D. Long crack in the crust of Earth.
      5. _____ Pele, Vulcan, and Kashima  E. measure of the strength of an earthquake
      6. _____ Epicenter  F. Seismic sea wave caused by an earthquake, hurricane, or underwater landslide.
      7. ___Compression-Shear-Surface  H. The three types of earthquake waves.






      8. _____Volcano  A. A volcano that has not erupted in recorded time and is not considered to do
      9. ____ Dormant Volcano  B. An opening in the surface of the Earth in which molten rock and gas can escape
      10._____Extinct Volcano  C. Bowl shaped depression located at the top of the main vent in a volcano
      12._____ Magma  D. Molten rock found under the surface of the Earth
      13._____Lava  E. A volcano that is resting 
      14._____Conduit  F. Molten rock found under the surface of the Earth
      15._____Crater  G. The main passageway for magma in a volcano

      16-21. Name the three ways that volcanoes form and describe the process of formation for each.
      16.







      17.





      18.




      19. Why do earthquakes occur?




      20. Where do most of the world's earthquakes occur?



      21. How does a volcano grow larger?


       

      Name the volcanic term for each letter.
      A._____ D._____  

      B._____ E._____

      C._____ F._____ 

    Chapter 2 Test Answer Key

    Test Chapter 2
    Earthquakes and Volcanoes

    Name____________________

    1.  ___D___ Fault  A. gods and goddesses of ancient mythology
    2.  ___B___Focus  B. The three types of earthquake waves.
    3.  ___E___Magnitude  C. The point on the surface of the Earth directly above the earthquake.
    4.  ___F___Tsunami  D. Long crack in the crust of Earth.
    5.  ___A___Pele, Vulcan, and Kashima  E. measure of the strength of an earthquake
    6.  ___C___ Epicenter  F. Seismic sea wave caused by an earthquake, hurricane, or underwater landslide.
    7.  ___B___Compression-Shear-Surface  H. Exact point of origin of an earthquake. Usually found deep under the surface of the Earth.



    9.  ___B___Volcano  A. A volcano that has not erupted in recorded time and is not considered to do
    10. ___E___Dormant Volcano  B. An opening in the surface of the Earth in which molten rock and gas can escape 
    11. ___A___Extinct Volcano  C. Bowl shaped depression located at the top of the main vent in a volcano
    12. ___F___Magma  D. Molten rock found on the surface of the Earth
    13. ___D___Lava  E. A volcano that is resting
    14. ___G___Conduit  F. Molten rock found under the surface of the Earth
    15. ___C___Crater  G. The main passageway for magma in a volcano


    16-21. Name the three ways that volcanoes form and describe the process of formation for each.

    1. Volcanoes can form at subduction zones where two plates collide, one being driven down into the mantle and the other riding over the top. This causes the lithospheric plate to melt and being less dense than the rock in the mantle it will rise. This rising magma will produce a volcano.

    2. Volcanoes can form at a mid-ocean ridge. When the two plates separate magma fills the void and a volcano is produced. These chains of volcanic mountains are the longest mountain chain in the world.  

    3. Volcanoes can also form at a hot spot.



    22. Why do earthquakes ocurr? Earthquakes occur because the Earth's plate are in motion. The plates do not move smoothly and evenly. Great stresses build up along the plate boundaries. When a plate moves suddenly a great amount of energy is released in the form of wave energy. These waves are what cause the damage from an earthquake.

    23. Where do most of the world's earthquakes occur? Along plate boundaries. The main earthquake zones are the Circum-Pacific belt that stretches around the rim of the Pacific Ocean and the Alpide Belt in Europe and Asia.

    24. How does a volcano grow larger? Volcanoes grow from their eruptions. When avolcano erupts it ejects lava, or pyroclasts, or both that builds the cone larger and larger.


     
    Name the volcanic term for each letter.
    A. Magma Chamber D. Conduit 

    B. Dike E. Crater

    C. Side Vent F. Layers of lava and ash

    Lesson #4 Goals, Objectives, and Materials

    Goals, Objectives and Materials
    For Lesson #4
    "Earthquakes-The Rolling Earth"

    Goals:

    To familiarize students with the processes that cause earthquakes.

    Objectives: 

    The students will:

    1. Become familar with and be able to demostrate how earthquake waves are produced;

    2. Become familar with the different types of fault zones;

    3. Become familar with the causes of earthquakes.


    Materials: 

    1. One copy of the Content Lesson #4 for each student

    2. Plastic Table
    3. Three cups of sand
    4. Rubber Mallet
    5. Jump Rope
    6. Slinky

    Lesson #5 Goals, Objectives, and Materials

    Goals, Objectives and Materials
    For Lesson #5
    "Volcanoes"

    Goal:

    To familiarize students with the processes that cause volcanoes to form.


    Objectives: 

    The students will:

    1. Become familar with the 3 ways that volcanoes form;

    2. Become familar with legends and myths associated with volcanoes;

    3. Become familar with and be able to use vocabulary associated with volcanism


    Materials: 

    1. One copy of the Content Lesson #5 for each student

    2. Toothpaste in a tube
    3. Cardboard
    4. scissors
    5. 1 plastic bottle of seltzer of soda
    6. 1 small bottle of food coloring

    Lesson #6 Goals, Objectives, and Materials

    Goals, Objectives and Materials
    For Lesson #6
    "Volcanic Terms"

     

    Goals:

    To familiarize students with the vocabulary associated with volcanic processes and the basic structure of a volcano itself.

    Objectives: 

    The students will:

    1. Become familiar with the processes and concepts that create and build volcanoes;
    2. Become familiar with the vocabulary terms associated with volcanic processes;

    Materials: 


    1. Hands-On Lesson Plan Sheet

    2. Five colors of modeling clay or playdough-Red, Brown, Gray, Black, Blue

    3. 10 X 12 sheets of tag board

    4. Felt tip pen for labeling

    5. Thick Thread

    Lesson #4 Content Center

    Content Center 

    (Earthquakes-The Rolling Earth) 

    (Lesson #4) 

    The San Andreas Fault

    The San Andreas fault runs through the state of California from the Mexican border northward to the city of San Francisco. The cities of San Diego and Los Angeles lay on west side of the fault, which is actually the Pacific Plate. San Francisco lays on the east side of the fault, which is the North American Plate. (See map #1)  
    The North American Plate is a very large plate which consists of the west side of the Atlantic Ocean, Greenland, and all of the North American continent except the part of California west of the San Andreas fault. This plate is moving west at about 1 inch per year. The Pacific Plate is also a very large plate that is moving north northwest at an astonishing rate of over 3 inches per year. Many earthquakes are recorded on the San Andreas fault each year as these two plates slide by each other. Another interesting fact is that Los Angeles which is about 375 miles southeast of San Francisco today is moving north toward San Francisco. In about 100 million years Los Angeles will actually be north of San Francisco if the plates keep moving at the same speed and direction that they are today. (See map #2)
    The San Andreas fault has been studied thoroughly because of it's location so close to many major cities and universities. The San Andreas fault is located directly on the surface of the Earth which makes it easy to view and study. It can be seen riding in a car, walking on a hike, and an even better view can be seen from an airplane. The effects of the movement on the fault line are seen in crooked or offset fences, roadways, stream beds and railroad tracks.
    The San Andreas fault is a strike-slip fault.  Strike-slip faults are not collision faults like subduction zones and they are not separating plate zones like mid-ocean ridges. A strike-slip fault is a plate boundary where two plates slide past each other. See diagram 1 below. Diagram 1 (Courtesy of FEMA) 

    Tsunamis
    A tsunami is a large water wave that is formed by a volcanic eruption, underwater earthquake, landslide, or a hurricane. Tsunamis are the most dangerous of all the wave types. Tsunamis have the potential to reach heights of 120 feet (Krakatoa's eruption of 1883) and speeds of over 500 miles per hour. When the wave is far out at sea it can go unnoticed because almost all of the wave stays under the surface of the ocean. When the waves reaches the shallow water of the coastline the height of the wave grows to its fullest and then crashes down on the land.  
    Tsunamis have killed thousands of people. When Krakatoa erupted in 1883 it sent out a tsunami that killed 36,000 people. The great Alaskan earthquake in 1964 sent out a tsunami that killed over 60 people in Hilo, Hawaii.  

    Thought and Discussion Questions 

    1. Describe in your own words what a fault is.


    2. How is a strike-slip boundary different from a collision and separation boundary?


    3. What is a tsunami?


    4. How does a tsunami form?

    Lesson #5 Content Center

    Content Center 

    (Lesson #5)
    Volcanoes
    "The Lost Continent of Atlantis"

    Have you ever heard of the lost continent of Atlantis? Where was the lost continent of Atlantis? Historians have speculated that it was in the middle of the Atlantic Ocean, off of the coasts of both Spain and France, and also in the western Mediterranean Sea. We do not know for sure where it was, but in 1956 a Greek seismologist by the name of Angelos Galanopoulos suggested that the great continent was located in the eastern Mediterranean Sea. More specifically south of Greece on the island of Santorini, which was called Thera in 1650 B.C. He believed a great volcanic eruption was the end to this wonderful civilization.



    Plato, a great Greek poet and historian, was fascinated with an ancient Egyptian story of a fantastic civilization which was lost during a terrible catastrophe. 
    Plato called this civilization Atlantis. He depicted Atlantis as the greatest civilization of its time. The people were famous for their beauty and their culture. Plato wrote about this beautiful place one thousand years after it was destroyed. His writings were based on ancient Egyptian writings and his translation of the language was questionable.  
    Plato made a mistake in his math!!! He claimed the lost continent to be about ten times the size that it actually was. He also put the time of the calamity to be about 9000 years before the rise of the great Athenian empire, which was about 10 times earlier than it could have really occurred. Historians now believe that Atlantis was destroyed about 900 years before Athens. A factor of ten was the problem with Plato's accounts, ten times too large and ten times too early.  
    What happened to wipe this superior civilization off the face of the Earth? A great volcanic eruption was the cause. A volcano named Santorini exploded with such fury that it not only blew most of the island into the heavens but also caused a huge tsunami that wiped out many of the neighboring civilizations.  
    When Santorini erupted, much of the volcanic cone exploded into the atmosphere and over 32 square miles of the island was destroyed. What happened next was the formation of a caldera. A caldera is a bowl shaped depression caused by the magma chamber under the volcano emptying during an eruption and the volcano falling into the magma chamber because of its own weight. When the caldera formed, a series of tsunamis produced by the crashing of the top of the volcano wiped out many cities and towns in the eastern Mediterranean. This tsunami was reported to have reached the height of over 300 feet. The explosion was heard as far away as Sweden, and the earthquakes produced knocked down walls in Crete over 100 miles away!! Historians believe these giant sea waves were what caused the mysterious end of the great Minoan civilization in the Mediterranean. 
    Archaeologists have recovered artifacts from the island lately that show a great ancient civilization was present on Thera about 3800 years ago. The artifacts have come from the sunken part of the island far under the surface of the sea. This evidence helps us to believe that Santorini may be the "Lost Continent of Atlantis"!!!!

    Questions

    1. What caused great civilizations in the Mediterranean to disappear about 1650 B.C.?




    2. What is a caldera?




    3. What caused the production of a huge tsunami over 300 feet tall?







    Lesson #4 Hands-on Center

    Hands-On Center
    (Earthquakes-The Rolling Earth)
    Lesson #4
    Earthquake Waves
    Shock Waves

    Materials: 

    1. Plastic Table
    2. Three cups of sand
    3. Rubber Mallet







    1. The students will pour three cups of sand on the top of a plastic table near the edge.  
      They will tap the table lightly with the rubber mallet. When they tap the table lightly they will see the sand "jump" into the air.  
      The teacher should explain that as rocks snap and break at the focus of an earthquake shock waves are sent out in all directions. The "jumping sand" represents the release of the energy from the hammer through the plastic table.  
    2. The students should move the sand farther away from the point of contact and see what happens.  
      The farther away the sand is from the source of energy (tapping of rubber mallet) the less the sand jumps. This represents the fact that the farther you are from 
      the epicenter the less you will feel the earthquakes shock waves.
    3. The students should move the sand to the opposite side of the table and tap lightly. They should observe a very small movement of the sand.

    4. Shear Waves
      Materials: Jump Rope
      Two students will hold the ends of the jump rope and raise their hands up and down shaking the jump rope and producing S waves. The waves in the jump rope will have an up and down motion.  

      The teacher will explain that the S waves of an earthquake look like the waves produced by the shaking of the jump rope. These are secondary waves and they will learn more about these in the lesson "Earthquakes-The Rolling Earth" on the computer.

      Compression Waves
      Materials: 
      1. Slinky


      Two students will hold the Slinky at the two ends pulling and stretching it slightly. One student will push the Slinky 
      slowly watching the Compression wave as it rolls from one end of the Slinky to the other. The teacher will explain that the waves produced with the Slinky are like Compression or Primary waves of an earthquake. The students will learn more about compression waves in the lesson "Earthquakes- The Rolling Earth" on the computer.

    Lesson #5 Hands-on Center

    Hands-on Center 

    (Volcanoes)
     Lesson #5

    Erupting Volcano


    Materials: 

    1. 3 small plastic bottles of seltzer of soda
    2. 1 small bottle of food coloring


    The teacher should conduct the following experiment. Wearing safety goggles and old clothing is advised. The experiment could ruin clothing and hurt unprotected eyes. Follow the steps below having the students write down what they observe and hear.

    1. Show the students the bottle before it is opened explaining that the gases dissolved in the liquid are under much more pressure than gases outside the bottle. As the bottle is opened the gas (Carbon Dioxide) will be visible as it escapes creating bubbles and a hissing sound.

    2. add 3 drops of red food coloring


    1. put the plastic cap back on the bottle 
    2. shake the bottle profusely hold the bottle over a sink or drain- tell the students that the liquid inside the bottle represents magma, which is molten rock and gas inside the Earth.  

    3. turn the cap slowly allowing the "lava" to erupt-tell the students that as magma escapes to the surface it is then called lava.  

    The teacher should explain that the liquid has dissolved gases in it (Carbon Dioxide), just as magma has many dissolved gases in it.  

    When the bottle is not open the students will not be able to see the gas because the liquid has the gas disolved in it. Because of the higher pressure in the bottle you can not see the gas bubbles. When the bottle is opened the students will see the gas escape. The liquid will erupt out with the gas because it is under more pressure than the outside environment. When magma rises in the conduit the pressure falls as it nears the surface of the Earth. The lava will escape violently as the pressure drops for the same reasons that the soda water escaped with the carbon dioxide gas. When a volcano erupts the lava may be very frothy from the escaping gases. This is true especially if the magma has a high gas content. The most violent eruptions are due to a great build up of pressure from magma that has a high gas content. Magmas with little dissolved gas usually do not erupt violently.

    Lava Dome Building 


    Materials: 

    1. Toothpaste in a tube
    2. Cardboard
    3. scissors


    Cut a hole in the cardboard so that the neck of the opened toothpaste tube fits into the hole. Squeeze the tube lightly so that a little toothpste comes out then stop. Explain that the toothpaste is very thick and pasty like dactitic lava is. This is the same lava that has built the lava dome in the crater in Mt. St. Helens. Squeeze the tube again and stop, explaining that the dome was built very slowly with these same starting and stopping motions. The dome grew for seven years and has basically halted its growth as of 8/20/95.  
    The dome that is in the crater in Mt. St. helens today is not the only dome that has occupied this space. Another dome grew during the first month after the original eruption but blew up in June of 1980.  
    Continue the same pattern of squeezing and stopping until the students understand the concept of dome growth.

    Lesson #6 Hands-on Center

    Hands-On Center 

    (Volcanic Terms-Lesson #6)

    A Model of a Strato Volcano

    Materials: 

    1. Five colors of modeling clay or playdough-Red, Brown, Gray, Black, Blue
    2. Thumb Tacks
    3. 10 X 12 sheets of tag board
    4. Felt tip pen for labeling
    5. Thick Thread


    There will be no Content Lesson today because the Hands-On lesson will take at least a half-hour.
    The students will build a volcano model on tag board. The students will add lava and ash layers one by one simulating the process that builds a real strato volcano cone.  
    The students will start by building the upper layer of the mantle and lower crust with a magma chamber and conduit like the diagram below.


    The students will then start to build the strato volcano model by rolling "snakes" that will represent the alternating layers of hardened lava (Black clay)and ash (Gray clay). They will need to add an extension to the conduit (Red clay) with each set of layers added. As they build the volcano higher have the students add a fissure (Red clay) and a lava flow (Red clay) down the flank of the cone.
    When the students are finished making the model have them label it by writing the following terms on the tag board and connecting the terms to the model with pins. (See Diagram below)

    Discussion Questions

    Lesson 4 "Earthquakes-The Rolling Earth" 


     

    Thought and Discussion Questions 

    1. Describe in your own words what a fault is.

    2. How is a strike-slip boundary different from a convergent and divergent boundary?


    3. What is a tsunami?

    4. How does a tsunami form?

    Hyperstudio Questions
    1. How are earthquake waves produced?

    2. What does a Richter Scale show?


    3. What are the differences between compression, shear, and surface  
    waves?



    Lesson #5 Volcanoes
    Discussion Questions #5
    1. What caused the death of so many people during the second eruption of Vesuvius?

    2. What is a pyroclastic flow?

    Hyper Studio Questions #5
    1. Where do volcanoes form?

    2. What are the two definitions for the term volcano.

    3. Write definitions in your own word for the following terms:
    a) Active Volcano-
    b) Dormant Volcano-
    c) Extinct Volcano-

     
    Lesson #6 Volcanic Terms
    No Content Lesson Today
    Hyperstudio Questions
    Label the following parts of a volcano by writing your answers on a sheet of paper.
    A.  
    B.  
    C. 
    D.  
    E.  
    F.  


    Discussion Questions Answer Key

    Answer Key 

    Discussion and Hyperstudio Questions


     
     
     

    Lesson 4 "Earthquakes-The Rolling Earth" 


    Thought and Discussion Questions 

    1. Describe in your own words what a fault is.
    A fault is a long crack in the crust of the Earth. They can be associated with plate boundaries or can be produced from earthquakes. 

    2. How is a strike-slip boundary different from a convergent and divergent boundary?
    A strike-slip boundary occurs where two plates are sliding past each other in opposite directions. It is like a tear in the crust of the Earth.
    A convergent boundary occurs where two plates collide. Sometimes one plate is driven under the other, other times the two plates force themselves up into high mountains. 
    A divergent boundary occurs where two plates are separating. The two plates are moving in opposite directions causing new crust to be formed. These occur at mid-ocean ridges. 

    3. What is a tsunami?
    A tsunami is a very large sea wave. These waves can be up to 100 feet high when they break on the coastline. 
    4. How does a tsunami form?
    Tsunamis are caused by 1) an earthquake 2) an underwater landslide 3) or a volcanic eruption.
    Hyperstudio Questions
    1. How are earthquake waves produced?
    When an earthquake occurs the energy produced from the movement of the plates of the Earth radiates out from the focus in the form of seismic waves. 

    2. What does a Richter Scale show?
    The Richter scale is a measure of the strength and length of time that earthquake lasts. 

    3. What are the differences between compression, shear, and surface  
    waves?
    Compression waves are the fastest waves produced from an earthquake. Because of their speed they arrive at the surface first and are also called P (Primary) waves. They hit the surface with a pounding or jackhammer motion.
    Shear waves are about half the speed of P waves. They arrive later and thus called S (Secondary) waves. They hit the surface with a rolling, up and down motion.  
    Surface waves are the last waves to strike the surface and are confined to the upper layers of the Earth. The are the slowest waves and cause the most damage. There are two kinds of surface waves Love and Rayleigh waves.  



    Lesson #5 Volcanoes
    Discussion Questions #5
    1. What caused the death of so many people during the second eruption of Vesuvius?
    The pyroclastic flow of very hot steam, gas, and ash. The flow was probably over 700 degrees and moving at a rate of over 70 miles per hour. 
    2. What is a pyroclastic flow?
    A very turbulent mixture of steam, gases, ash, and small pieces of rock that is heavier than air and moves at a high rates of speed. Some pyroclastic flows are over 900 degrees F. with speeds in excess of 100 miles per hour. 

    Hyper Studio Questions #5
    1. Where do volcanoes form?
    Volcanoes form at subduction zones, mid-ocean or rift zones, and at hot spots 
    2. What are the two definitions for the term volcano.
    1) A volcano is an opening in the Earth's surface in which molten rock called magma and gases can escape. 2) The mountain that is formed by repeated volcanic eruptions. 
    3. Write definitions in your own word for the following terms:
    a) Active Volcano-A volcano that is currently erupting or has erupted in recorded time. 
    b) Dormant Volcano-A volcano that is not currently erupting but has erupted in recorded time and is considered likely to do so again. 
    c) Extinct Volcano-A volcano that has not erupted in recorded time and is not likely to do so. 

    Lesson #6 Volcanic Terms
    No Content Lesson Today
    Hyperstudio Questions
    Label the following parts of a volcano by writing your answers on a sheet of paper.
    A.  Magma Chamber 
    B.  Dike 
    C.  Side Vent 
    D.  Conduit 
    E.  Crater 
    F.  Layers of lava and ash