Chapter 8: Earthquakes and Earth s Interior Section 1: What is an Earthquake? I. Earthquakes Group # Main Idea:

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1 Chapter 8: Earthquakes and Earth s Interior Section 1: What is an Earthquake? I. Earthquakes Group # A. Focus and Epicenter Group # B. Faults Group # II. Cause of Earthquakes Group # A. Elastic Rebound Hypothesis Group # B. Aftershocks and Foreshocks Group # Section 2: Measuring Earthquakes I. Earthquake Waves Group # A. Surface Waves Group # B. Body Waves Group # II. Locating an Earthquake Group # A. Earthquake Distance Group # B. Earthquake Direction Group # C. Earthquake Zones Group #

2 II. Measuring Earthquakes Group # A. Richter Scale Group # B. Moment Magnitude Group # C. Modified Mercalli Scale Group # Section 3: Destruction from Earthquakes I. Seismic Vibrations Group # A. Building Design Group # B. Liquefaction Group # II. Tsunami Group # A. Causes of Tsunamis Group # B. Tsunami Warning System Group # III. Other Dangers Group # IV. Predicting Earthquakes Group #

3 A. Short-Range Predictions Group # B. Long-Range Forecasts Group # Section 4: Earth s Layered Structure I. Layers Defined by Composition Group # A. Crust Group # B. Mantle Group # C. Core Group # II. Layers Defined by Physical Properties Group # A. Lithosphere and Asthenosphere Group # B. Lower Mantle Group # C. Inner and Outer Core Group # III. Discovering Earth s Layers Group # IV. Discovering Earth s Composition Group # What are 5 effects of Earthquakes? (Pgs. 238 & 239)

4 Chapter 9: Plate Tectonics Section 1: Continental Drift I. An Idea Before its Time Group # A. Evidence: The Continental Puzzle Group # B. Evidence: Matching Fossils Group # C. Evidence: Rock Types and Structures Group# D. Evidence: Ancient Climates Group# II. Rejecting A Hypothesis Group # A. A New Theory Emerges Group # Section 2: Plate Tectonics I. Earth s Major Plates Group # II. Types of Plate boundaries Group#

5 A. Divergent boundaries Group # B. Convergent boundaries Group # C. Transform fault boundaries Group # Section 3: Actions at Plate Boundaries I. Divergent boundaries Group # A. Oceanic Ridges and Seafloor Spreading Group # B. Continental Rifts Group # II. Convergent Boundaries Group # A. Oceanic-Continental Group # B. Oceanic-Oceanic Group # C. Continental-Continental Group #

6 III. Transform Fault Boundaries Group # Section 4: Testing Plate Tectonics I. Evidence for Plate Tectonics Group # A. Paleomagnetism Group # B. Earthquake Patterns Group # C. Ocean Drilling Group # D. Hot Spots Group # Section 5: Mechanisms of Plate Motion I. Causes of Plate Motion Group # A. Slab-Pull and Ridge-Push Group # B. Mantle Convection Group #

7 Chapter 8 Earthquakes and Earth s Interior Section 8.1 What Is an Earthquake? This section explains what earthquakes and faults are and what causes earthquakes. Reading Strategy Building Vocabulary As you read this section, write a definition for each vocabulary term in your own words. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Vocabulary earthquake a. Definition b. c. d. e. f. g. 1. Circle the letter of the approximate number of major earthquakes that take place each year. a. about 50 b. about 75 c. about 3000 d. about 30,000 Earthquakes Match each description with its earthquake feature. Description 2. Earth vibration caused by rapid energy release 3. energy that radiates in all directions from the earthquake origin 4. fracture where movement has occurred 5. surface location directly above where an earthquake originates 6. location within Earth where an earthquake originates Earthquake Feature a. epicenter b. focus c. seismic wave d. fault e. earthquake Earth Science Guided Reading and Study Workbook 55

8 Chapter 8 Earthquakes and Earth s Interior Cause of Earthquakes 7. Is the following sentence true or false? It was not until after the 1906 San Francisco earthquake was studied that the actual cause of earthquakes was understood. 8. Complete the flowchart to show the sequence of events that occur when rocks are deformed along a fault. A. Forces in Earth act on rocks on both sides of a fault. B. C. D. Energy is released. 9. The hypothesis states that when rocks are deformed, they bend and then break, releasing stored energy. 10. What causes most earthquakes? 11. Is the following sentence true or false? Most earthquakes occur along existing faults. 12. Circle the letter of small Earth movements that occur following a major earthquake. a. foreshocks b. slippage c. aftershocks d. foci 13. The has been studied more than any other fault system in the world. 14. What is fault creep? Earth Science Guided Reading and Study Workbook 56

9 Chapter 8 Earthquakes and Earth s Interior Section 8.2 Measuring Earthquakes This section discusses types of seismic waves and how earthquakes are located and measured. Reading Strategy Outlining As you read, fill in the outline with the important ideas in this section. Use the green headings as the main topics and the blue headings as subtopics. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. I. Earthquake Waves A. Surface Waves B. II. A. B. C. III. A. B. Measuring Earthquakes Earthquake Waves 1. The figure shows a typical recording of an earthquake. Select the appropriate letter in the figure that identifies each of the following types of earthquake waves. surface wave S wave Pwave 2. Circle the letter of the name of the recording of the three types of earthquake waves in the figure. a. seismograph b. seismogram c. seismic wave d. travel-time graph A B C Earth Science Guided Reading and Study Workbook 57

10 Chapter 8 Earthquakes and Earth s Interior 3. Circle the letter of the type of earthquake wave that shakes particles at right angles to their direction of travel. a. P waves b. S waves c. surface waves d. compression waves Locating an Earthquake 4. Is the following sentence true or false? On a seismogram, the greater the interval is between the arrival of the first P wave and the first S wave, the greater the distance to the earthquake source. 5. Is the following sentence true or false? You can use travel-time graphs from two seismographs to find the exact location of an earthquake epicenter. 6. Most major earthquakes occur around the outer edge of the Ocean. 7. List the active earthquake areas in the circum-pacific belt. Measuring Earthquakes 8. What two types of measurements do scientists use to describe the size of earthquakes? Match each description with its term related to earthquake measurement. Description Term 9. derived from the amount of a. intensity displacement that occurs along b. magnitude a fault zone c. Richter scale 10. based on the amplitude of the largest seismic wave recorded d. moment magnitude scale on a seismogram 11. measure of the size of seismic waves or amount of energy released at the earthquake source 12. measure of the amount of earthquake shaking at a location based on damage 13. What is the most widely used measurement for earthquakes? 14. Why is the answer to question 13 the most widely used measurement for earthquakes? Earth Science Guided Reading and Study Workbook 58

11 Chapter 8 Earthquakes and Earth s Interior Section 8.3 Destruction from Earthquakes This section discusses damage caused by earthquakes and explains how earthquakes are predicted. Reading Strategy Monitoring Your Understanding Preview the Key Concepts, topic headings, vocabulary, and figures in this section. List two things you expect to learn. After reading, state what you learned about each item you listed. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. What I Expect to Learn a. b. What I Learned c. d. Seismic Vibrations 1. List three factors that affect the degree of damage that occurs to structures as a result of earthquakes. 2. Circle the letter of the structure that is least likely to be damaged in a major earthquake. a. steel-frame building b. nonflexible wood-frame building c. unreinforced stone building d. unreinforced brick building 3. What risk does liquefaction pose during an earthquake? Earth Science Guided Reading and Study Workbook 59

12 Chapter 8 Earthquakes and Earth s Interior Tsunamis 4. Complete the table about tsunamis. Tsunamis Definition Causes Areas Protected from Tsunamis by Warning System a. b. 5. Is the following sentence true or false? Most earthquakes generate tsunamis. Other Dangers 6. The sinking of the ground caused by earthquake vibrations is called ground. 7. During an earthquake, violent shaking can cause soil and rock on slopes to fail, resulting in. Predicting Earthquakes 8. Circle the letter of the things that scientists measure along faults or fractures when predicting future earthquakes. a. temperature of well water b. building damage c. carbon dioxide emissions d. radon gas emissions 9. Is the following sentence true or false? Methods used to make short-range earthquake predictions have not been successful. 10. Is the following sentence true or false? Scientists are able to make accurate long-term earthquake predictions based on their understanding of how earthquakes occur. 11. What do scientists call an area along a fault where no earthquake activity has occurred for a long time? Earth Science Guided Reading and Study Workbook 60

13 Chapter 8 Earthquakes and Earth s Interior Section 8.4 Earth s Layered Structure This section describes Earth s layers and their composition. Reading Strategy Sequencing After you read, complete the sequence of layers in Earth s interior. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Earth s Internal Structure lithosphere a. b. outer core c. Layers Defined by Composition 1. Use the figure of Earth s structure to write the letter(s) that represents each of the following layers. mantle continental crust oceanic crust core B A C Depth (km) 100 D km 2270 km 5 40 km 2885 km E F G Earth Science Guided Reading and Study Workbook 61

14 Chapter 8 Earthquakes and Earth s Interior Layers Defined by Physical Properties 2. Use the figure of Earth s structure on the previous page to write the letter that represents each of the following layers. inner core asthenosphere outer core lithosphere Match each description with its Earth layer. Description 3. soft, weak rock with some melting 4. liquid iron-nickel alloy that generates Earth s magnetic field 5. cool, rigid crust and uppermost mantle 6. solid iron-nickel alloy Earth Layer Discovering Earth s Layers 7. The boundary called the separates the crust from the mantle. 8. Is the following sentence true or false? Geologists concluded that the outer core was liquid because P waves could not travel through it. 9. Why do P waves bend when they travel into the outer core from the mantle? Discovering Earth s Composition a. asthenosphere b. inner core c. outer core d. lithosphere Match each composition with its Earth layer. Composition Earth Layer 10. basaltic rock a. continental crust 11. granitic rock b. oceanic crust 12. similar to stony meteorites c. core 13. similar to metallic meteorites d. mantle 14. that collide with Earth provide evidence of Earth s inner composition. 15. Is the following sentence true or false? Until the late 1960s, scientists had only seismic evidence they could use to determine the composition of oceanic crust. Earth Science Guided Reading and Study Workbook 62

15 Chapter 9 Plate Tectonics Section 9.1 Continental Drift This section explains the hypothesis of continental drift and the evidence supporting it. Reading Strategy Summarizing Fill in the table as you read to summarize the evidence of continental drift. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Hypothesis Continental Drift Evidence a. continental puzzle b. c. d. An Idea Before Its Time 1. The figure shows Earth s ancient supercontinent as it appeared about 300 million years ago, according to Alfred Wegener. Write the letter that represents each of the following present-day continents. Antarctica Europe and Asia South America India North America Africa C A F D E B G Australia 2. Wegener called Earth s ancient supercontinent shown in the figure. Earth Science Guided Reading and Study Workbook 63

16 Chapter 9 Plate Tectonics Match each example of continental drift with the type of evidence it is. Evidence for Example Continental Drift 3. Similar mountain chains run a. rock types and structures through eastern North America b. matching fossils and the British Isles. c. continental puzzle 4. Land areas that show evidence of ancient glaciation are now located d. ancient climates near the equator. 5. The Atlantic coastlines of South America and Africa fit together. 6. Remains of Mesosaurus are limited to eastern South America and southern Africa. 7. evidence for continental drift includes several fossil organisms found on different landmasses. 8. Is the following sentence true or false? If the continents existed as Pangaea, the rocks found in a particular region on one continent should closely match in age and type those in adjacent positions on the adjoining continent. Rejecting a Hypothesis 9. Circle the letter of an example of one objection that critics had about Wegener s continental drift hypothesis. a. Wegener could not provide any evidence to support continental drift. b. Wegener could not propose a mechanism capable of moving the continents. c. Wegener s idea of the mechanism capable of moving the continents was physically impossible. d. Wegener s fossil evidence was not accurate. 10. Is the following sentence true or false? Most scientists in Wegener s time supported his continental drift hypothesis. 11. Is the following sentence true or false? Wegener proposed that during continental drift, larger continents broke through the oceanic crust. 12. By 1968, data collected about the ocean floor, earthquake activity, and the magnetic field led to a new theory called. 13. The new theory that replaced Wegener s hypothesis explained most geologic processes, including the formation of. Earth Science Guided Reading and Study Workbook 64

17 Chapter 9 Plate Tectonics Section 9.2 Plate Tectonics This section discusses plate tectonics, including lithospheric plates and types of plate boundaries. Reading Strategy Comparing and Contrasting After you read, compare the three types of plate boundaries by completing the table. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Boundary Type convergent a. divergent b. transform fault c. Relative Plate Motion Earth s Major Plates Match each definition with its term. Definition Term 1. weaker region in the mantle over a. lithosphere which Earth s outer shell lies b. plates 2. segments of the lithosphere that c. plate tectonics move and change shape d. asthenosphere 3. rigid layer of the uppermost mantle and crust 4. theory that states that the lithosphere is divided into plates that move 5. Earth s largest plate is the plate. 6. What is one way in which the continental drift hypothesis and the plate tectonic theory differ? 7. Circle the letter of the number of major plates there are on Earth. a. 3 b. 7 c. 8 d Is the following sentence true or false? The lithospheric plates move at about 5 km per year. Earth Science Guided Reading and Study Workbook 65

18 Name Class Date Chapter 9 Plate Tectonics Types of Plate Boundaries 9. Identify each type of plate boundary shown in the figure. A. B. A. B. C. 10. Circle the letter of the type of C. plate boundary that occurs when a plate of oceanic lithosphere plunges beneath an overriding plate of continental crust. a. divergent b. spreading center c. convergent d. transform fault 11. Circle the letter of the type of plate boundary that occurs when a plate of continental crust grinds past another plate of continental crust. a. divergent b. spreading center c. convergent d. transform fault 12. Is the following sentence true or false? Each of Earth s plates contains only one of the three types of plate boundaries. 13. Is the following sentence true or false? Plates shrink and grow in area. 14. The East African Rift valley is an example of what kind of plate boundary? 15. The San Andreas Fault zone in California is an example of what kind of plate boundary? Earth Science Guided Reading and Study Workbook 66

19 Chapter 9 Plate Tectonics Section 9.3 Actions at Plate Boundaries This section discusses seafloor spreading, subduction zone, and transform fault boundaries. Reading Strategy Outlining Complete the outline. Use the green headings as the main topics and the blue headings as subtopics. As you read, add supporting details. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Actions at Boundaries I. Divergent Boundaries A. B. II. A. B. C. III. Divergent Boundaries 1. Is the following sentence true or false? Oceanic lithosphere is created at divergent boundaries. 2. Is the following sentence true or false? Divergent boundaries only occur on the ocean floor. Match each definition with its term. Definition Term 3. process by which plate a. seafloor spreading tectonics produces new b. rift valley oceanic lithosphere c. oceanic ridge 4. deep faulted structure found along a divergent boundary 5. elevated seafloor along a divergent boundary 6. Circle the letter of the age of the oldest parts of the ocean floor. a. 18 million years old b. 80 million years old c. 180 million years old d. 180 billion years old Earth Science Guided Reading and Study Workbook 67

20 Chapter 9 Plate Tectonics Convergent Boundaries 7. Select the appropriate letter in the figure that identifies each of the following features. C A B E F 100 km G D Melting 200 km Sinking oceanic lithosphere Oceanic crust Trench Continental volcanic arc Continental lithosphere Continental crust Asthenosphere 8. Circle the letter of the description of a subduction zone. a. where an oceanic plate is forced beneath a second plate b. where an oceanic plate grinds past a second plate c. where a continental plate grinds past a second plate d. where an oceanic plate moves away from a second plate 9. Newly formed land consisting of an arc-shaped island chain is called a(n). 10. Is the following sentence true or false? Mountains form as a result of a collision between two continental plates. Transform Fault Boundaries 11. What happens at a transform fault boundary? 12. Circle the letter of the example of a transform fault boundary that is NOT located in an ocean basin. a. the San Andreas Fault b. the Aleutian Trench c. the Himalayan mountains d. the Nazca plate Earth Science Guided Reading and Study Workbook 68

21 Chapter 9 Plate Tectonics Section 9.4 Testing Plate Tectonics This section discusses the evidence supporting the theory of plate tectonics, including paleomagnetism. Reading Strategy Predicting Write a prediction of where earthquakes will occur. After you read, if your prediction was incorrect or incomplete, write where earthquakes actually occur. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Probable Locations a. b. Actual Locations Evidence for Plate Tectonics 1. has occurred when rocks formed millions of years ago show the location of the magnetic poles at the time of their formation. 2. Is the following sentence true or false? When magnetic mineral grains in a rock form, they become magnetized in the direction parallel to Earth s existing magnetic field. 3. Circle the letter of the statement representing some of the strongest evidence of seafloor spreading. a. Similar fossils are found in North America and Europe. b. Earth s magnetic filed periodically reverses polarity. c. Strips of alternating polarity lie as mirror images across the ocean ridges. d. Evidence of glaciation occurs on land in tropical and subtropical regions. Earth Science Guided Reading and Study Workbook 69

22 Chapter 9 Plate Tectonics 4. Circle the letter of the definition of reverse polarity. a. the loss of magnetism by iron-rich mineral grains when heated b. the gain of magnetism by iron-rich mineral grains when cooled c. what rocks that show the same magnetism as the present magnetic field have d. what rocks that show the opposite magnetism as the present magnetic field have 5. New basalt rocks currently forming at the oceanic ridges show since they become magnetized according to the present magnetic field. 6. Is the following sentence true or false? The absence of deepfocus earthquakes along the oceanic ridge system is inconsistent with the theory of plate tectonics. 7. Is the following sentence true or false? Deep-focus earthquakes occur away from ocean trenches within the slab of lithosphere descending into the mantle. 8. Where do shallow-focus earthquakes occur relative to ocean trenches? 9. Circle the letter of the location of the oldest oceanic crust, according to ocean drilling data. a. at the continental margins b. at the ridge crest c. between the continental margins and ridge crest d. deep in the asthenosphere 10. Circle the letter of the location of the youngest oceanic crust, according to ocean drilling data. a. at the continental margins b. at the ridge crest c. between the continental margins and ridge crest d. deep in the asthenosphere 11. A(n) is a volcanic area on a plate where a plume of mantle material rises. 12. Is the following sentence true or false? Both hot spot evidence and data on the ages of seafloor sediment support the theory of plate tectonics. 13. Circle the letter that correctly completes the following sentence. No earthquakes have been recorded below a. 70 km. b. 700 km. c km. d. 70,000 km. Earth Science Guided Reading and Study Workbook 70

23 Chapter 9 Plate Tectonics Section 9.5 Mechanisms of Plate Motion This section explains what causes plate motion and the role played by unequal distribution of heat within Earth. Reading Strategy Identifying Main Ideas As you read, write the main ideas for each topic. For more information on this Reading Strategy, see the Reading and Study Skills in the Skills and Reference Handbook at the end of your textbook. Topic Slab-pull a. Main Idea Ridge-push b. Mantle convection c. Causes of Plate Motion 1. Circle the letter of the basic force that drives plate tectonics. a. Earth s magnetic field b. convection in the mantle c. tidal influence of the moon d. radiation from the sun 2. What happens to the material involved during convection? 3. The motion of matter called results from convection. 4. The mechanism called causes oceanic lithosphere to slide down the sides of the oceanic ridge. Earth Science Guided Reading and Study Workbook 71

24 Chapter 9 Plate Tectonics 5. The mechanism that is the primary downward arm of the mantle s convection flow is. 6. Is the following sentence true or false? The upwardly flowing arms in mantle convection consist of mantle plumes of rising hot rock. 7. Select the letter of the figure that shows each of the following mantle convection models. Whole-mantle convection model Deep-layer model A Volcanic trail Upper mantle Hot spot Mantle plume Lower mantle Oceanic ridge B Descending oceanic plate Volcanic trail Upper mantle Rising plume Hot spot Lower mantle Oceanic ridge 660 km Core Core 8. Circle the letter of the statement that best describes the deep-layer model. a. Rock magnetism changes as rock layers melt under heat and pressure. b. Hot oceanic lithosphere descends into the mantle, and cold mantle plumes move heat toward the surface. c. Cold oceanic lithosphere descends into the mantle, and hot mantle plumes move heat toward the surface. d. Heat from Earth s interior causes layers of convection to slowly swell and shrink in complex patterns. 9. Circle the letter of the statement that best describes the wholemantle convection model. a. Rock magnetism changes as rock layers melt under heat and pressure. b. Hot oceanic lithosphere descends into the mantle, and cold mantle plumes move heat toward the surface. c. Cold oceanic lithosphere descends into the mantle, and hot mantle plumes move heat toward the surface. d. Heat from Earth s interior causes layers of convection to slowly swell and shrink in complex patterns. 10. What causes thermal convection in the mantle? Earth Science Guided Reading and Study Workbook 72