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Earth Forces Course Notes Calderglen High School By the end of this unit you should know about…. The structure of the Earth Continental Drift The Earth’s plates and how they move Volcanoes and Earthquakes. Calderglen High School Geography Department -1- Lesson 1: The Structure of the Earth The shape of the Earth is a sphere. It is divided into different layers. Ever wondered what our earth is made of? Think of it as an apple. An apple constitutes the skin, the pulp and the core in the middle. Similarly, the earth is made up of a series of layers, that is: the crust; the mantle; the inner core; and the outer core. Each of these is described below. Mantle Inner & outer core Skin The core is at the very centre of the Earth and is the hottest layer, reaching temperatures of 5,500°C. The diagram shows that there is a molten outer core and a solid inner core. The inner core is a solid ball, composed mainly of Iron. Test your vocabulary! What does the word ‘molten’ mean? Calderglen High School Geography Department -2- The crust floats on a layer of semi-molten rocks called the mantle. The mantle is the thickest layer of the earth (approximately 3000km) and consists of semimolten rocks. Molten rock in the mantle is called magma. The crust is the Earth’s hard and rocky surface and is the thinnest layer. The crust of the Earth is not one solid piece like the skin of an apple. The Earth’s crust is not a huge, solid piece of rock. Instead it is broken up into large pieces which we call plates. No-one has actually travelled to the centre of the Earth. What we do know about the inside of the Earth comes from studying earthquakes and volcanoes, just like we will do later in this unit. So if we took a slice out of the Earth this is what it would look like (Figure 1.1): Figure 1.1: Inside the Earth Calderglen High School Geography Department -3- Table 1.1 summarises the characteristics of the inside of the Earth. Table 1.1: Characteristics of the layers of the Earth Name of Layer Crust Mantle Outer Core Inner Core Thickness (km) 10-60 3000 2000 1300 Temperature (˚C) 10 375 5500 6000 State Solid Semi-molten Molten Solid Activity 1: The Structure of the Earth (a) Your teacher will give you a diagram of the Earth’s Structure. Using the word bank below, complete diagram 1 to show the different layers of the Earth. Once this diagram is completed, get scissors and glue and stick it in your jotter. Wordbank Crust Inner Core Mantle Outer Core b) Using Table 1.1 annotate your diagram with information about thickness, temperature and state. c) Colour your diagram in, using a different colour for each layer. Stick it in your jotter! Calderglen High School Geography Department -4- Moving Plates Figure 2.1: The Seven Main Plates Direction of plate movement The crust of the Earth is not one solid piece like the skin of an apple. The crust is made up of pieces that fit together like a jigsaw. We call these plates. These plates move slowly across the earth’s surface – much the same rate as your fingernails grow (50mm each year). Where the plate edges meet is called a plate boundary. These plates move slowly across the earth’s surface – much the same rate as your fingernails grow (50mm each year). Where the plate edges meet is called a plate boundary. It is at plate boundaries that most earthquakes and volcanic eruptions take place, and where the highest mountains occur. Calderglen High School Geography Department -5- The plates move because the mantle underneath the plates moves, as it is heated by the enormous heat generated from the core of the Earth. This movement is called a convection current. The movement of these currents is similar to the movement of convection currents in a pot of boiling water. Figure 2.2: Magma heats up and rises Activity 2: Moving Plates Instructions: 1. Using Figure 2.2. Identify and label the 8 main plates on to your diagram 2. Name each continent. You can use an atlas to help you. 3. Colour each plate in a different colour so you can easily identify each one. Calderglen High School Geography Department -6- Lesson 2: Continental Drift The plates on top of the mantle have been moving very slowly for many millions of years. The movement of these plates is known as Continental Drift. If we could travel back in time the shape of our continents would be very different from today. Over 200 million years ago all the continents were joined together forming a huge super-continent called Pangaea (Figure 3.1). Travelling forward in time to 135 million years ago the continents started to drift apart (Figure 3.2). Today the continents are in the positions shown in Figure 3.3. The continents are still moving very slowly, 1-3 mm every year. In the future, perhaps 100 million years from now, the continents will look very different from the shapes we know today. Figure 3.1: The continents 200 million years ago Calderglen High School Geography Department -7- Figure 3.2: The continents 135 million years ago Figure 3.3: The continents today The British Isles lies on top of one of the plates and it has been moving for many millions of years (Figure 3.4). Figure 3.4: The Movement of the British Isles Calderglen High School Geography Department -8- Evidence for Continental Drift Although humans were not there at the time, there is evidence to support the theory of continental drift. If you look at the continents of South America and Africa on a map, they seem to fir together, a bit like a jigsaw puzzle . The same types of fossilised animals and plants have been found in South America and Africa. There are similar rock formations found in South America and Africa. This evidence suggests that these continents were not always separate as they are today, but that they were joined together at some point in the past. Calderglen High School Geography Department -9- Activity 3: Continental Drift Sorting Task 1. Collect a blank storyboard and a set of continental drift cards from your teacher. 2. In your group you must sort these into the correct order to tell the story of continental drift. Activity 4: Continental Drift 1. Look at the map below which shows Pangaea. Name the continents numbered 1, 2, 3, 4 and 5. (Hint: Use Figure 3.3 to help you) Asia Europe 1 2 3 4 5 2. Figure 3.4 shows the movement of the British Isles over the last 500 million years. Describe the path that Britain has taken. Calderglen High School Geography Department - 10 - Lesson 3: Plate Tectonics Plate Boundary Types The point at which the Earth’s plates meet is called a plate boundary. Because the Earth’s plates are moving many of the Earth’s and earthquakes and volcanic eruptions take place at found at plate boundaries where the Earth’s crust is weakest. The Earth’s plates can move in three directions: Some slide past each other (sliding plates), Some move towards each other (colliding plates), and Some move away from each other (parting plates). Direction of plate movement Sliding Plates As sliding plates move past each other friction builds up. Just like if you rub the palms of your hands together! Calderglen High School Geography Department - 11 - Sliding plates occur when two plates move alongside each other. Sliding plates can cause earthquakes. An earthquake is produced when plates stick as they are sliding past each other. The pressure between the two plates builds up and then they jolt apart. It is the jolting motion that produces earthquakes. Colliding Plates As the plates collide the weaker plate is forced under the stronger plate! Colliding plates are two plates which move towards each other and then collide into each other. During the collision of the two plates mountains are formed. Earthquakes and volcanoes can also be produced. Parting Plates Parting plates are two plates which are moving away from each other. When the plates move apart, hot molten rocks called magma wells up to fill the gap between the plates. This hot magma then cools down and a new crust is formed. Calderglen High School Geography Department - 12 - Figure 4.4 shows the main plates of the Earth. The arrows show the plates that are sliding, colliding or parting. Figure 4.4: World Plates and their Movement Activity 5: Plate Movements Instructions: 1. Make a copy of Diagrams 4A, 4B and 4C. Draw arrows on the diagrams to show the movements of the three types of plates. Diagram 4A: Parting Plates Diagram 4B: Colliding Plates Diagram 4C: Sliding Plates Calderglen High School Geography Department - 13 - 2. Draw arrows to show the direction of the moving plates on your world map plate tectonics diagram from Lesson 1 (in your jotter). 3. Put an X at the place where the plates are parting. 4. Put a Y at the place where the plates are colliding. 5. The arrows on Figure 4.4 show the direction in which each plate is moving. Copy the sentences below and delete the words that are wrong. a) The Eurasian plate is moving (towards/away from) the North American plate. b) The Eurasian plate is moving (towards/away from) the Pacific plate. c) The South American plate is moving (towards/away from) the Nazca plate. 6. Answer the following questions using Figure 4.4. a. Name 3 plates with continents on them. b. Name two plates without continents on them. c. Name the plate on which Britain is located. d. Which two plates divide New Zealand? Calderglen High School Geography Department - 14 - Lesson 4: Location of Earthquakes and Volcanoes Earthquakes and volcanoes are found approximately in the same places. Figure 5.1 shows the location of earthquakes on the crust of the Earth. Figure 5.1: Location of Earthquakes The pattern is that the earthquakes are found along the edges or boundaries of the plates. At the boundary of plates (the area where two plates meet) the plates are either sliding, colliding or parting. It is these movements that cause earthquakes. Figure 5.2 shows the location of the world’s volcanoes. Most of the world’s volcanoes are found at the plate boundaries. Figure 5.2: Location of Volcanoes Calderglen High School Geography Department - 15 - The pattern is that the volcanoes are found along the edges or boundaries of the plates Figure 5.3 shows the location of earthquakes and volcanoes along the plate boundaries of the Earth. There is a clear pattern to be seen. Earthquakes and volcanoes are usually found along the boundary of the world’s plates. Figure 5.3: Location of Earthquakes, Volcanoes and World Plates Calderglen High School Geography Department - 16 - Activity 6: Location of Earthquakes and Volcanoes Read these statements and choose 3 which are correct- copy these into your jotter : • Earthquakes and volcanoes happen everywhere. • Earthquakes and volcanoes often happen in the same places. • Earthquakes and volcanoes happen in the ocean as well as on land. • Earthquakes and volcanoes only happen in hot countries. • Earthquakes and volcanoes happen mainly on large continents. • Earthquakes and volcanoes occur along plate boundaries and fault lines. Activity 7: Location of Earthquakes and Volcanoes Instructions: 1. Draw Table 5.1 and use Diagram 5A to match up the numbered volcanoes to the correct name for each. (You may wish to use an Atlas). Table 5.1 Volcano Name Number Mt. Kilimanjaro Mt. Pelee Mt. Fuji Tristan da Cunha Mt. Etna Krakatoa Paricutin Mt. St Helens Mt. Vesuvius Surtsey Hawaii Canary Islands Calderglen High School Geography Department - 17 - Diagram 5A 5 1 4 10 3 6 2 12 9 8 11 7 2. Study Figures 5.2 and 5.3 in this booklet. Where are most volcanoes found? 3. Draw Table 5.2 and use Diagram 5B to match up the numbered earthquakes to the correct place name for each. (You may wish to use an Atlas). Table 5.2 Place Name Number San Francisco Mexico City Peru Mindanao Armenia Turkey Guatemala Iran China Bucharest Papua/New Guinea Indonesia Calderglen High School Geography Department - 18 - Diagram 5B 5 6 7 8 12 11 10 1 2 9 4 3 4. Study Figures 5.1 and 5.3 in this booklet. Are earthquakes found along the boundary of the plates or in the middle of the plates? Give reasons for your answer. Calderglen High School Geography Department - 19 - Lesson 5: Volcanoes How is a Volcano Formed? Millions of years ago, magma forced its way between two plate tectonic boundaries The process repeated over and over again. The cooled lava formed layers of rock The lava cooled and turned into rock. Many years later magma forced its way up again In between, the volcano spewed out ash and steam. The ash settled on the volcano and cemented into rock Calderglen High School Geography Department Over millions of years, the layers built up to form a volcano - 20 - Volcanoes are formed by molten material rock from the mantle. It is called magma and is forced through an opening in the Earth’s crust called a vent. Figure 6.1: Features of a Volcano The Main Features of a Volcano Description Original crust Rocks which existed before the volcano Magma chamber Large underground pool of magma below the volcano Pipe or vent Central tube which magma travels through, this is how lava reaches the surface Crater The hole at the top of a volcano where lava and ash escape. Gas & Dust cloud Fine fragments of rock, minerals and volcanic glass created during eruptions and thrown into the air above the crater Lava bombs Large pieces of rock thrown out of the volcano Pyroclastic flow A cloud of very hot ash which rolls down the side of a volcano Layers of ash & lava Build up to create the shape of a volcano Lava flow Hot molten rocks flow down the side of the volcano Calderglen High School Geography Department - 21 - We can describe volcanoes depending on when they last erupted. Active volcanoes: recently erupted and are likely to erupt again. Dormant (sleeping) volcanoes: show no sign of erupting, but could erupt again in the future. Extinct volcanoes: have shown no signs of erupting over the last 10,000 years and are highly unlikely to erupt again. Arthur’s Seat in Edinburgh is a good example, this volcano was active about 340 million years ago. Activity 8: Volcanoes 1. Make a sketch of Diagram 6A. Using the information from Figure 6.1, label your sketch with the following terms: Crater Lava Bombs Magma Chamber Lava Flow Main Vent Gas & Dust Cloud Layers of Ash &Lava Pyroclastic Flow Original Crust Diagram 6A 2) Using your diagram of ‘An Active Volcano’ and the information above, describe what happens when a volcano erupts by putting the following stages in order. Calderglen High School Geography Department - 22 - A volcanic eruption gas, steam, ash and lava bombs are blown out through the crater lava flows down the side of the volcano magma builds up under great pressure in the magma chamber magma erupts through the vent 3.What do you think is meant by: a. An active volcano? b. A dormant volcano? c. An extinct volcano? Calderglen High School Geography Department - 23 - Lesson 6,7 and 8: Volcanoes Case Study-Eyjafjallajokull, Iceland Eyjafjallajokull, (pronounced ay-yah-FYAH-plah-yer-kuh-duhl). In March 2010, magma broke through the crust beneath Eyjafjallajokull glacier. This was the start of two months of dramatic and powerful eruptions that would have an impact on people across the globe. It erupted twice in 2010—on 20 March and in April/May. The March event forced a brief evacuation of around 500 local people, but the 14 April eruption was ten to twenty times more powerful and caused substantial disruption to air traffic across Europe. It caused the cancellation of thousands of flights across Europe and to Iceland. Timeline of events 20th March 2010 – Small eruptions start from the volcano. 12th April 2010 – Hundreds of small earthquakes happen; a sign that a bigger eruption is on the way. 13th April 2010 – A large eruption happens directly underneath a large amount of ice causing it to melt. The water mixes with lava and creates a huge ash cloud. 14th April 2010 – The ash cloud from the volcano reaches up 8km into the sky. 15th April 2010 – Ash has blown all over Europe, causing countries to close their air space and stop planes. 17th April 2010 – The eruption continued but less explosively meaning that the amount of ash being erupted was getting smaller, however countries still had to close airspace as the ash already in the air spread out over Europe. 19th April 2010 – The first countries reopened their airspace; including Germany, Poland and Switzerland. 20th April 2010 – All airspace was reopened and it was safe for planes to fly over Europe again. Calderglen High School Geography Department - 24 - Figure 7.1: Airspace affected by the eruption Green: Iceland Orange: Countries that stopped some flights. Red: Countries that stopped all flights Figure 7.2: Ash Cloud on 16th of April 2010 Calderglen High School Geography Department - 25 - Lesson 9: Earthquakes An earthquake is a sudden movement of the rocks in the Earth’s crust. The quick movement of the rocks sends shock waves through the crust (like when you throw a stone into a pond) and when they reach the surface, the ground shakes resulting in an earthquake. Earthquakes are very common – there is one somewhere in the world every 2 minutes. Figure 9.1: Shock Waves on A Pond Figure 9.2: Shock Waves on the Ground Calderglen High School Geography Department - 26 - Earthquakes start below the Earth’s surface at a point called the focus. The shock waves spread out from this point. The epicentre is the point on the Earth’s surface directly above the focus. The epicentre is the place where the earthquake is felt most and causes the most damage. Earthquakes are measured by a special instrument called a Seismograph (Figure 7.3). A Seismograph is an extremely sensitive instrument that records tremors of the Earth’s surface. Figure 9.3: A Seismograph The strength of an earthquake can be shown on a scale known as the Richter Scale. The Richter scale begins at 0 and continues to 12. The higher the number the greater the strength of the earthquake (Figure 9.4). Calderglen High School Geography Department - 27 - Figure 7.4: The Richter Scale Each point on the Richter Scale is 10 times greater than the one before. On this scale, scale 6 would be 10 times more powerful than scale 5, and scale 7 would be 10 times more powerful than scale 6. Calderglen High School Geography Department - 28 - Activity 9: Earthquakes Write out the paragraph below and use the words to fill in the blanks. earthquake plate jolt stick fault faults crust plates pressure How earthquakes are caused: The Earth’s c____ contains many cracks. These cracks are called f_____. The main f____ lines are found along the p____ boundaries. When two p_____ slide past each other the movement is so slow that it is hardly noticed. Sometimes, the plates s____ together and p_______ builds up. Eventually the plates free themselves with a j___ which shakes the ground violently. This violent shaking is called an e_________. Activity 10: Effects of an Earthquake Copy Diagram 9A onto a separate sheet of paper. Create a picture board to show some of the effects of an earthquake. Diagram 9A Effects of an Earthquake Buildings collapse People injured and killed Water pipes burst Tsunamis (tidal waves) Fires break out Roads damaged Calderglen High School Geography Department - 29 - Activity 11 Table 9B below shows the number of deaths from various earthquakes. Draw a bar graph showing these deaths. (Hint: It should look like the one in Diagram 9C) Table 7.1: Deaths From Earthquakes Date Location Deaths 1906 San Francisco, USA 1000 1985 Mexico City, Mexico 10000 1976 Guatemala 23000 1986 El Salvador 1500 1980 Naples, Italy 4800 1977 Romania 1500 1980 Algeria 4500 1982 North Yemen 23000 1968 Khurusan, Iran 12000 1978 Tabas, Iran 25000 1976 Philippines 8000 1976 Turkey 4000 Diagram 9C 1976 1976 1978 1968 1982 1980 1977 1980 1986 1976 1985 28000 26000 24000 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 1906 (Deaths) Deaths From Earthquakes (Year) Calderglen High School Geography Department - 30 - Extension Task 1. Use an Atlas to locate these earthquakes. Lesson 10 and 11: Case Study: Nepal Earthquake On Saturday April 25th, 2015, a huge earthquake struck the Himalayan nation of Nepal. The quake flattened large parts of the capital Kathmandu and caused widespread devastation. Figure 7.2 shows the location of Nepal. Figure 7.2: Location of Nepal The Indo-Australian Plate pushes against the Eurasian plate and has caused the formation of Himalayan Mountains. These mountains are still growing by around 1cm a year! The huge pressure that builds up at this plate boundary was suddenly released as the plates jerked apart, causing the earthquake. The earthquake measured 7.8 on the Richter Scale. Calderglen High School Geography Department - 31 - Impact of the earthquake The earthquake is Nepal's worst natural disaster in 80 years. More than 8,000 people are known to have died in Nepal. 13,932 have been injured across the country. The United Nations estimates that eight million people have been affected. UNICEF estimates that 1.7 million children live in the worst-hit areas. The impacts of the earthquake can be classified into social, economic and environmental impacts. Social Impacts are impacts on people. For example, people’s houses may be destroyed. Economics Impacts are impacts on the wealth of an area. For example, it may be very expensive to rebuild destroyed buildings. Environmental Impacts are impacts on the landscape. For example, landslides or flooding. Calderglen High School Geography Department - 32 - Activity 12: Nepal Earthquake Your teacher will show you some images from the Nepalese earthquake. In your jotter write down at least 10 effects of the earthquake. Once you have done this, classify each effect into social, economic or environmental effects. Activity 13: Aid Effort Working in a group, decide what help would be needed after the Earthquake. Draw a mind map in your jotter to show your thoughts. Activity 14: Earthquake Survival Kit The Nepalese Prime Minister has told all locals to put together an earthquake emergency kit that would be useful in the event of another earthquake. What do you think would be essential to have in the event of an earthquake? Draw a diagram of a rucksack in your jotter and think of as many items as possible that you might need to survive. Once you have finished, swap with your neighbour and compare answers. Add in any items that you have missed out. Activity 15: Earthquake Survival Flyer Create a flyer that will be given to people living in earthquake hazard zones. You need to give them 3 top tips for surviving an earthquake. Try to convince people to do these things, so justify why it is important. Include diagrams! Calderglen High School Geography Department - 33 - Calderglen High School – Geography Department Evaluation Sheet Name Topic Earth Forces Mark/Level Second Year 1. Circle the number, which reflects your feelings about the course you have just completed. Very enjoyable Very easy Varied work Lots of Video/internet H/W interesting Quality workguides Help available Lots of encouragement 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 Not enjoyable Very difficult Repetitive Few videos/ internet H/W boring Poor quality No help available Little encouragement 2. What part of the course did you particularly like? 3. What part of the course did you particularly dislike? 4. Suggest 3 things that you will do to help your learning in the next topic. 5. Suggest any improvements that can be made to the unit to make it more interesting/easier to learn. Calderglen High School Geography Department - 34 -