Understanding Plate Tectonics: Key Concepts and Relationships

Plate Tectonic Activity Sheet -5 120 points As always, I t’s all about relationships. As you prepare for exam-2, review the content below and formulate relationships between tectonic plate boundaries, plate boundary interactions, tectonic plate processes and landforms created by plate interactions.. In many cases, don’t memorize, but explain in your own words and develop a picture in your mind regarding plate tectonic concepts. . Most importantly, as you learn the concept and relationship, be able to explain the concept using the proper terminology. Please make sure you take a look at the probable exam essay questions at the end of this activity sheet. It’s recommended that you view the plate tectonic lecture in its entirety before answering questions. 1. Observing the first plate tectonic intro slide on the lecture discussion, , explain in your own words what this slide is telling you about plate tectonics. ● Plate tectonics is a widely held scientific idea that the earth’s lithosphere is made up of a number of huge tectonic plates that have been slowly moving in our earth for around 3.4 billion years. 2. Who is Alfred Wegener? What simple observation did Alfred Wegener make to begin the thought of moving continents? ● Alred Wegener was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher who lived from November 1880 to November 1930. Wegener found similarities in the coastlines between South America and Western Africa. To summarize, Wegener developed a scientific hypothesis that both lands have been part of a supercontinent called Pangea, which had split and steadily drifted apart over geological time. Wegener had no evidence to figure out how the continents moved, and the scientist laughed at him for no evidence. a. Relationship Questions: 1. Why would Alfred make this observation between the continents Africa and South America? And what simple instrument did he use to make this observation? ● The continents of South America and Africa appeared to fit quite well if the Atlantic Ocean were removed, these two gigantic landforms would lock neatly together. A map was the key component he used to make this conclusion 2. What evidence did Alfred Wegner present to initiate the Continental Drift hypothesis? And the existence of Pangaea? ● On January 6, 1912, he presented his continental drift concept. He looked for rocks, geological features, and fossils that were on both sides of the Atlantic Ocean. He discovered a striking resemblance between the continents’ corresponding sides, particularly. 3. Important -- How old is suggested for the supercontinent Pangaea? ● Supercontinent Pangea began to break up around 225-200 million years ago, according to the continental drift theory. 3. During the mid to late 1920’s, Alfred spent time compiling evidence to support his Continental Drift hypothesis. a. Relationship Questions: 1. Explain in detail the three lines of evidence given by Alfred to support the existence of Pangaea. ● He believed in the existence of a supercontinent known as Pangea. The rock formation, fossils, and the puzzle pieces form of the continents are the three main pieces of evidence. 2. Draw diagrams that show these three lines of evidence 3. If you lived during the time of these proposals (1920’s), why would you have a problem with Alfred’s proposal of moving continents? ● If I lived during the time of Wagener suggested his hypothesis, I would not believe him due to conditioning and as well as the impossibility of large chunks of land moving due to the earth’s centrifugal force. 4. Moving through the proposed continental drift historical timeline (after the 1920’s) more evidence of moving continents came to light that supports the continents are on the move. a. Relationship Questions: 1. Explain why advances were made after the 1920’s that begins to support moving continents.

● The accumulation of substantial evidence about Wegener’s idea was made feasible by the technological breakthrough necessary by world war II, eventually refining and supplementing Wegener’s theory of continental drift with a modern tectonic theory 2. What discoveries were made that Alfred was unaware of that indicates continents are on the move. ● Seismometers were developed to monitor ground shaking induced by nuclear testing, and magnetometers were developed to detect submarines. Researchers used seismometers to uncover that earthquakes tended to occur in certain locations rather than evenly around the globe. Scientists using magnetometers on the seafloor discovered evidence of unexpected magnetic changes near submarine ridges: altering bands of rock recorded from the earth’s magnetic field. 3. Explain the process of seafloor spreading a. How significant is this process to plate movement ● The idea of plate tectonics uses seafloor spreading to explain continental drift. Tensional stress generates fractures in the lithosphere when the oceanic plates diverge. Magma rises up the fissures cools on the ocean floor to generate new sea bed at a spreading center b. If sea floor spreading averages about 2-3 mm of movement per year, explain how scientists make the argument the seafloor is actually moving. ● The earth’s magnetic history is thus preserved in the expanding ocean floors, producing a continuous record of the movement of the ocean floors. The examination of the fracture zones that offset the parts of the ridge had yielded more supporting evidence. c. If the Mid-Atlantic ridge produces new ocean floor at 2-3 mm/yr resulting in the separation of Africa and South America, what can be concluded about the age of the earth? ● 3.3 to 3.2 billion years ago, continental landmasses began to rise above sea level, 700 million years more than most models indicate. d. What can one conclude regarding geological activity on the ocean floor versus the continents where we live? ● Divergent plate boundaries cause seafloor spreading. The heat from the mantle’s convection currents causes the crust to become more flexible and less thick as tectonic plates progressively drift apart. The less dense material rises, generating a sea bed mountain or raised area, and the crust eventually cracks. It does not pose any danger to us because it takes a very long time to occur. 5. During the late 1950’s and into the 1960’s, IMPORTANT evidence known as paleomagnetism showed the sea floor as a conveyor belt system that moves continental material. a. Relationship Questions: 1. How is paleomagnetism related to seafloor spreading? ● Paleomagnetism provides important evidence for the theories of plate tectonics. The ocean floor is mostly composed of basalts which are iron-rich. They record the alignment of the magnetic field surrounded by the ridge (sea floor spreading). The magnetic poles had different locations relative to the continent than they are today. 2. Describe the processes of paleomagnetism using terms: magma, magnetic reversals, mirror image, north/south reversals, seafloor spreading, iron particles, ● When magntiism on the seafloor is studied, similar magnetism of similar magnetism minerals (iron particles) orients themselves wig the earth’s magnetism. Earth’s magnetism is not always constant, with time it revers (north-south reversal). If we go away from the ridge, we found older rocks. 3. How does the concept of paleomagnetism separate Alfred Wegener’s Continental Drift hypothesis from the theory of Plate Tectonics. ● Wegenr’s theory states that continental drift occurs by the rotation of the earth, he couldn’t explain what force is responsible for the drifting of such large plates. 4. Did the discovery of magnetic reversals change the way scientists view the movement of continents in the late 1960’s? Explain

● Yes, from the paleomagnetism evidence, it is seen that the magnetic poles had different locations relative to the continent than they are today. Magnetic minerals of one continent do not point to the same pole position as with comparison from the same time period on another continent. 6. Plate Tectonics ---- Using the lecture slide “The Theory of Plate Tectonics” ------ a. Relationship Questions: 1. In your own words and drawing a diagram, describe the general model outlining how continents are able to move. 2. What is meant by the phrase “Continents are along for the ride” ● It means that continents are moving always along different plate margins called plate tectonics. The evidence of this is ocean spreading which causes a rift valley. 3. Briefly describe the three types of plate tectonic boundaries ● Convergent boundary: This is the boundary where plates destruct, one plate has a high density and the other has a lower density. ● Divergent boundary: This is the constructive boundary, where two plates move away from each other and a new plate is formed ● Transform plate boundary: This is when plates slide past one another. 7. The Divergent boundary a. Relationship Questions: 1. How is the divergent boundary related to seafloor spreading? ● Seafloor spreading occurs at divergent plate margins. Beneath all plates magma is present when heat variation occurs in magma convection current will occur which will result for the movement of plates 2. How would you describe the interconnected pattern of divergent boundaries circumventing the earth’s surface ● The mid-ocean ridge system is a massive undersea mountain range that covers 23% of the earth’s surface and is along the middle of the mid-ocean ridge. 3. Given the nature of divergent and convergent boundary mechanics, explain why the seafloor is much, much younger than continental material. ● Convergent plate boundaries are locations, where two plates move toward one another. There are two plates, one is oceanic and the other is continental. One reason why the continental plate is older the places are moving apart and creating a way for the magma to rise. The magma rising is cooled by the seawater and becomes a part of the convergent boundary where the oceanic plate subducts and becomes a part of magma. 4. Describe the differences between seafloor spreading and continental rifting. ● A continental rift is defined as a lithosphere thinning process that leads to the continent's rupture and the emergence of a mid-oceanic ridge. Rifting is the first and most essential step in the process of separating two continents into two tectonic plates. Seafloor spreading, the geologic process of seafloor spreading occurs when tectonic plates large slabs of earth’s lithosphere - split from one another. a. How is the Mid-Atlantic ridge and the East African rift zone different, but related to divergence? ● The main difference is if the divergence between twe continental plates is a rift valley 5. Identify at least three geographical locations where divergent boundaries exist. ● Mid Atlantic ridge, Baikal, Antarctic Rift 8. The Convergent boundary a. Relationship Questions: 1. Three types of convergent boundaries ---- Draw a cross sectional diagram that shows each type of convergent boundary.

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2. Given your diagrams, describe the land feature differences between the ocean to continent (O-C) and ocean to ocean (O-O) boundaries. 3. In your own words, describe the geological mechanics taking place within the O-C and O-O boundaries that produce the land features described in #2 above. a. Explain why oceanic plate always subducts beneath the continental plate b. How does density play a role in the subduction of the O-O boundary. Use terms such as mafic and felsic to answer this question 4. Important! Write down at least 2 geographical locations on earth where there is evidence of an O-C and O-O plate convergence land features. Use the geographical locations presented in the lecture. 5. How is the continent to continent (C-C) boundary different than the O-C and O-O boundaries ● When two continental plates collide, they just smash together, this is just like what happens if you put your hands on two sides of a sheet of paper and bring your hands together, the material has nowhere to go but up. 6. Why is there the absence of subduction in the C-C boundary? ● Once the continental lithosphere reaches the subduction zone, subduction processes are altered, since the continental lithosphere is more buoyant and resists subduction beneath another continental lithosphere. 7. How is the Appalachian Mountains (Eastern USA) and Atlas Mountains (Morocco-Africa) related to the C-C boundary and Pangaea? ● Though they are separated by an ocean, Africa’s anti-atlas mountains and North America Appalachian mountains are linked in time. Both appear to have gotten their start hundreds of millions of years ago, before the end of the geologic era known as the Paleozoic 8. Identify at least 2 geographical areas where C-C boundaries exist today. ● C-C convergent boundaries are the collision of the India plate with the Eurasian plate, creating the Himalayan mountains, and the collision creating the series of ranges extending from the Alps in Europe to the Zagros mountains in Iran. The Rocky Mountains in North America is also a result of C-C continent collisions. 9. The Transform Boundary a. Relationship Questions: 1. Describe the mechanics or general motion of a transform boundary.

● A transform boundary is when two plates move away from the spreading center of a divergent plat boundary, each moving away from the other. 2. What is meant by “off-set” features produced by transform movement? ● The plates split away at different speeds, providing spacing between margins ranging from a few miles to several hundred miles. The active transform boundary is formed by this lateral movement. a. In your own words, describe how spreading ridges found on the ocean floor is affected by transform boundary movement. ● On the ocean floor, the majority of transform faults can be located. They usually are defined by shallow earthquakes and offset the active spreading ridges. b. How does the mechanics behind seafloor spreading and transform faulting move ocean floor material ● Heat from the mantle’s convection currents causes the crust to become more flexible and less thick as tectonic plates progressively drift apart. 3. What two geographical areas on earth shows the presence or a transform boundary located on continents ---- HINT (located in California and New Zealand) a. Draw a map that shows how the San Andreas Fault (SAF) location traversing through California 1. Label the Pacific and North American Plates and motion arrows (direction of plate movement) 2. Plot Los Angeles, San Francisco and Bakersfield on your map --- Which plates are these cities located? 3. Why is the SAF significant geologically? 10. Observe the animation regarding the evolution of the SAF -- how it formed a. Relationship Questions: 1. Describe what this animation is showing ---- age of SAF, how the fault forms (HINT: use the term subduction) ● Subduction is a geological process in which the oceanic lithosphere is recycled into the earth’s mantle at convergent boundaries, where the oceanic lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle a. What is the proposed age of the SAF ● The SAF is 28 million years old b. How does Bakersfield fit into the geological setting during the evolution of the SAF? ● Bakersfield is located on the North American plate. c. What is significant about the city of Parkfield, CA and how does Parkfield relate to the occurrence of the SAF? ● After an earthquake, the U.S geological survey and the California geological survey began the Parkfield earthquake experiment in the 1980s. Researchers from the USGS and collaborating institutions have created a dense network of instruments on the SAF at Parfield, California, where moderate EQs have occurred at fairly regular intervals./ 11. After answering questions 1-10 and completing activities, How would you characterize the theory of Plate Tectonics influence on the earth’s surface. You might want to consider these questions while answering a. Is your earth a dynamic earth --- always changing ● Yes it is b. Will your earth look different in 10 million years and beyond? ● It will change significantly c. What is the ring of fire and why is plate tectonics regarded as the universal theory. ● The ring of fire represents the results of plate tectonics. The plates are not fixed but are constantly moving atop a layer of solid and molten rock called the mantle.

d. Was Alfred Wegner onto something when he proposed his Continental Drift theory in the 1920’s ● People refer the continental drift as the taylor-wegener theory. Wegener foun that identical fossils could be foun on different continents, supporting his theory that continents which are now far apart were once linked. 12. The current scientific research regarding plate tectonics is “how do the plates” move --- the causes. a. Relationship Questions: 1. The term “convection” is used to describe the movement of plates. What is convection? Explain how convection works. ● COnvection currents describe the rising, spread, and sinking of gas, liquid, or molten material caused by the application of heat. 2. Thinking back to the interior parts of the earth (core, mantle, lithosphere), how is convection used to explain movement of continents. In your answer, use the general model of plate tectonics and explain the importance of the asthenosphere and convection results in “slab pull” ● Tectonic plates break apart and diverge where the mantle beneath is upwelling, Mid-ocean ridges develop (Ridge push), and the new lithosphere and crust form to replace the material that is moving away. Where plates converge, usually where the mantle is downwelling, one plate if forced beneath another. If the collision involves plates with he oceanic crust, subduction zones form where one plate descends into the mantle beneath the other plate (slab pull). Above these subduction zone chain of volcanoes and island arcs like the Aleutians, develop. 3. How does the lava-lamp theory explain what really is happening in the mantle when using convection processes? ● The earth’s manly has convection currents because of the heat of the core acts similarly to the light bulb in our lava lamp. The core’s heat energy is transferred to the mantle, causing it to rise toward the earth’s surface. Which is cooler. 4. Draw a diagram illustrating how convection and the lava-lamp theory move continental material. Possible Essay Questions: 1. What is the defining evidence that separates Wegner’s continental drift hypothesis from the theory of plate tectonics. ● The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, wegener published a paper explaining his theory that the continental landmasses were “drifting” across the earth, sometimes plowing through the oceans and into each other. 2. Explain the mechanics between the O-C, O-O and C-C convergent boundaries ● When plates converge, they do so in one of three settings: oceanic plates collide with each other O-O, Oceanic plates collide with continental plates O-C, or continental plates collide with each other forming C-C. 3. How is convection used to describe the movement of continents? a. Convection currents drive the movement of Earth’s rigid tectonic plates in the planet’s fluid molten mantle. In places where convection currents rise up towards the crust’s surface, tectonic plates move away from each other in a process known as seafloor spreading.

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Plate Tectonic Activity Sheet -5 120 points As always, I t’s all about relationships. As you prepare for exam-2, review the content below and formulate relationships between tectonic plate boundaries, plate boundary interactions, tectonic plate processes and landforms created by plate interactions.. In many cases, don’t memorize, but explain in your own words and develop a picture in your mind regarding plate tectonic concepts. . Most importantly, as you learn the concept and relationship, be able to explain the concept using the proper terminology. Please make sure you take a look at the probable exam essay questions at the end of this activity sheet. It’s recommended that you view the plate tectonic lecture in its entirety before answering questions. 1. Observing the first plate tectonic intro slide on the lecture discussion, , explain in your own words what this slide is telling you about plate tectonics. ● Plate tectonics is a widely held scientific idea that the earth’s lithosphere is made up of a number of huge tectonic plates that have been slowly moving in our earth for around 3.4 billion years. 2. Who is Alfred Wegener? What simple observation did Alfred Wegener make to begin the thought of moving continents? ● Alred Wegener was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher who lived from November 1880 to November 1930. Wegener found similarities in the coastlines between South America and Western Africa. To summarize, Wegener developed a scientific hypothesis that both lands have been part of a supercontinent called Pangea, which had split and steadily drifted apart over geological time. Wegener had no evidence to figure out how the continents moved, and the scientist laughed at him for no evidence. a. Relationship Questions: 1. Why would Alfred make this observation between the continents Africa and South America? And what simple instrument did he use to make this observation? ● The continents of South America and Africa appeared to fit quite well if the Atlantic Ocean were removed, these two gigantic landforms would lock neatly together. A map was the key component he used to make this conclusion 2. What evidence did Alfred Wegner present to initiate the Continental Drift hypothesis? And the existence of Pangaea? ● On January 6, 1912, he presented his continental drift concept. He looked for rocks, geological features, and fossils that were on both sides of the Atlantic Ocean. He discovered a striking resemblance between the continents’ corresponding sides, particularly. 3. Important -- How old is suggested for the supercontinent Pangaea? ● Supercontinent Pangea began to break up around 225-200 million years ago, according to the continental drift theory. 3. During the mid to late 1920’s, Alfred spent time compiling evidence to support his Continental Drift hypothesis. a. Relationship Questions: 1. Explain in detail the three lines of evidence given by Alfred to support the existence of Pangaea. ● He believed in the existence of a supercontinent known as Pangea. The rock formation, fossils, and the puzzle pieces form of the continents are the three main pieces of evidence. 2. Draw diagrams that show these three lines of evidence 3. If you lived during the time of these proposals (1920’s), why would you have a problem with Alfred’s proposal of moving continents? ● If I lived during the time of Wagener suggested his hypothesis, I would not believe him due to conditioning and as well as the impossibility of large chunks of land moving due to the earth’s centrifugal force. 4. Moving through the proposed continental drift historical timeline (after the 1920’s) more evidence of moving continents came to light that supports the continents are on the move. a. Relationship Questions: 1. Explain why advances were made after the 1920’s that begins to support moving continents.

● The accumulation of substantial evidence about Wegener’s idea was made feasible by the technological breakthrough necessary by world war II, eventually refining and supplementing Wegener’s theory of continental drift with a modern tectonic theory 2. What discoveries were made that Alfred was unaware of that indicates continents are on the move. ● Seismometers were developed to monitor ground shaking induced by nuclear testing, and magnetometers were developed to detect submarines. Researchers used seismometers to uncover that earthquakes tended to occur in certain locations rather than evenly around the globe. Scientists using magnetometers on the seafloor discovered evidence of unexpected magnetic changes near submarine ridges: altering bands of rock recorded from the earth’s magnetic field. 3. Explain the process of seafloor spreading a. How significant is this process to plate movement ● The idea of plate tectonics uses seafloor spreading to explain continental drift. Tensional stress generates fractures in the lithosphere when the oceanic plates diverge. Magma rises up the fissures cools on the ocean floor to generate new sea bed at a spreading center b. If sea floor spreading averages about 2-3 mm of movement per year, explain how scientists make the argument the seafloor is actually moving. ● The earth’s magnetic history is thus preserved in the expanding ocean floors, producing a continuous record of the movement of the ocean floors. The examination of the fracture zones that offset the parts of the ridge had yielded more supporting evidence. c. If the Mid-Atlantic ridge produces new ocean floor at 2-3 mm/yr resulting in the separation of Africa and South America, what can be concluded about the age of the earth? ● 3.3 to 3.2 billion years ago, continental landmasses began to rise above sea level, 700 million years more than most models indicate. d. What can one conclude regarding geological activity on the ocean floor versus the continents where we live? ● Divergent plate boundaries cause seafloor spreading. The heat from the mantle’s convection currents causes the crust to become more flexible and less thick as tectonic plates progressively drift apart. The less dense material rises, generating a sea bed mountain or raised area, and the crust eventually cracks. It does not pose any danger to us because it takes a very long time to occur. 5. During the late 1950’s and into the 1960’s, IMPORTANT evidence known as paleomagnetism showed the sea floor as a conveyor belt system that moves continental material. a. Relationship Questions: 1. How is paleomagnetism related to seafloor spreading? ● Paleomagnetism provides important evidence for the theories of plate tectonics. The ocean floor is mostly composed of basalts which are iron-rich. They record the alignment of the magnetic field surrounded by the ridge (sea floor spreading). The magnetic poles had different locations relative to the continent than they are today. 2. Describe the processes of paleomagnetism using terms: magma, magnetic reversals, mirror image, north/south reversals, seafloor spreading, iron particles, ● When magntiism on the seafloor is studied, similar magnetism of similar magnetism minerals (iron particles) orients themselves wig the earth’s magnetism. Earth’s magnetism is not always constant, with time it revers (north-south reversal). If we go away from the ridge, we found older rocks. 3. How does the concept of paleomagnetism separate Alfred Wegener’s Continental Drift hypothesis from the theory of Plate Tectonics. ● Wegenr’s theory states that continental drift occurs by the rotation of the earth, he couldn’t explain what force is responsible for the drifting of such large plates. 4. Did the discovery of magnetic reversals change the way scientists view the movement of continents in the late 1960’s? Explain

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● Yes, from the paleomagnetism evidence, it is seen that the magnetic poles had different locations relative to the continent than they are today. Magnetic minerals of one continent do not point to the same pole position as with comparison from the same time period on another continent. 6. Plate Tectonics ---- Using the lecture slide “The Theory of Plate Tectonics” ------ a. Relationship Questions: 1. In your own words and drawing a diagram, describe the general model outlining how continents are able to move. 2. What is meant by the phrase “Continents are along for the ride” ● It means that continents are moving always along different plate margins called plate tectonics. The evidence of this is ocean spreading which causes a rift valley. 3. Briefly describe the three types of plate tectonic boundaries ● Convergent boundary: This is the boundary where plates destruct, one plate has a high density and the other has a lower density. ● Divergent boundary: This is the constructive boundary, where two plates move away from each other and a new plate is formed ● Transform plate boundary: This is when plates slide past one another. 7. The Divergent boundary a. Relationship Questions: 1. How is the divergent boundary related to seafloor spreading? ● Seafloor spreading occurs at divergent plate margins. Beneath all plates magma is present when heat variation occurs in magma convection current will occur which will result for the movement of plates 2. How would you describe the interconnected pattern of divergent boundaries circumventing the earth’s surface ● The mid-ocean ridge system is a massive undersea mountain range that covers 23% of the earth’s surface and is along the middle of the mid-ocean ridge. 3. Given the nature of divergent and convergent boundary mechanics, explain why the seafloor is much, much younger than continental material. ● Convergent plate boundaries are locations, where two plates move toward one another. There are two plates, one is oceanic and the other is continental. One reason why the continental plate is older the places are moving apart and creating a way for the magma to rise. The magma rising is cooled by the seawater and becomes a part of the convergent boundary where the oceanic plate subducts and becomes a part of magma. 4. Describe the differences between seafloor spreading and continental rifting. ● A continental rift is defined as a lithosphere thinning process that leads to the continent's rupture and the emergence of a mid-oceanic ridge. Rifting is the first and most essential step in the process of separating two continents into two tectonic plates. Seafloor spreading, the geologic process of seafloor spreading occurs when tectonic plates large slabs of earth’s lithosphere - split from one another. a. How is the Mid-Atlantic ridge and the East African rift zone different, but related to divergence? ● The main difference is if the divergence between twe continental plates is a rift valley 5. Identify at least three geographical locations where divergent boundaries exist. ● Mid Atlantic ridge, Baikal, Antarctic Rift 8. The Convergent boundary a. Relationship Questions: 1. Three types of convergent boundaries ---- Draw a cross sectional diagram that shows each type of convergent boundary.

2. Given your diagrams, describe the land feature differences between the ocean to continent (O-C) and ocean to ocean (O-O) boundaries. 3. In your own words, describe the geological mechanics taking place within the O-C and O-O boundaries that produce the land features described in #2 above. a. Explain why oceanic plate always subducts beneath the continental plate b. How does density play a role in the subduction of the O-O boundary. Use terms such as mafic and felsic to answer this question 4. Important! Write down at least 2 geographical locations on earth where there is evidence of an O-C and O-O plate convergence land features. Use the geographical locations presented in the lecture. 5. How is the continent to continent (C-C) boundary different than the O-C and O-O boundaries ● When two continental plates collide, they just smash together, this is just like what happens if you put your hands on two sides of a sheet of paper and bring your hands together, the material has nowhere to go but up. 6. Why is there the absence of subduction in the C-C boundary? ● Once the continental lithosphere reaches the subduction zone, subduction processes are altered, since the continental lithosphere is more buoyant and resists subduction beneath another continental lithosphere. 7. How is the Appalachian Mountains (Eastern USA) and Atlas Mountains (Morocco-Africa) related to the C-C boundary and Pangaea? ● Though they are separated by an ocean, Africa’s anti-atlas mountains and North America Appalachian mountains are linked in time. Both appear to have gotten their start hundreds of millions of years ago, before the end of the geologic era known as the Paleozoic 8. Identify at least 2 geographical areas where C-C boundaries exist today. ● C-C convergent boundaries are the collision of the India plate with the Eurasian plate, creating the Himalayan mountains, and the collision creating the series of ranges extending from the Alps in Europe to the Zagros mountains in Iran. The Rocky Mountains in North America is also a result of C-C continent collisions. 9. The Transform Boundary a. Relationship Questions: 1. Describe the mechanics or general motion of a transform boundary.

● A transform boundary is when two plates move away from the spreading center of a divergent plat boundary, each moving away from the other. 2. What is meant by “off-set” features produced by transform movement? ● The plates split away at different speeds, providing spacing between margins ranging from a few miles to several hundred miles. The active transform boundary is formed by this lateral movement. a. In your own words, describe how spreading ridges found on the ocean floor is affected by transform boundary movement. ● On the ocean floor, the majority of transform faults can be located. They usually are defined by shallow earthquakes and offset the active spreading ridges. b. How does the mechanics behind seafloor spreading and transform faulting move ocean floor material ● Heat from the mantle’s convection currents causes the crust to become more flexible and less thick as tectonic plates progressively drift apart. 3. What two geographical areas on earth shows the presence or a transform boundary located on continents ---- HINT (located in California and New Zealand) a. Draw a map that shows how the San Andreas Fault (SAF) location traversing through California 1. Label the Pacific and North American Plates and motion arrows (direction of plate movement) 2. Plot Los Angeles, San Francisco and Bakersfield on your map --- Which plates are these cities located? 3. Why is the SAF significant geologically? 10. Observe the animation regarding the evolution of the SAF -- how it formed a. Relationship Questions: 1. Describe what this animation is showing ---- age of SAF, how the fault forms (HINT: use the term subduction) ● Subduction is a geological process in which the oceanic lithosphere is recycled into the earth’s mantle at convergent boundaries, where the oceanic lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle a. What is the proposed age of the SAF ● The SAF is 28 million years old b. How does Bakersfield fit into the geological setting during the evolution of the SAF? ● Bakersfield is located on the North American plate. c. What is significant about the city of Parkfield, CA and how does Parkfield relate to the occurrence of the SAF? ● After an earthquake, the U.S geological survey and the California geological survey began the Parkfield earthquake experiment in the 1980s. Researchers from the USGS and collaborating institutions have created a dense network of instruments on the SAF at Parfield, California, where moderate EQs have occurred at fairly regular intervals./ 11. After answering questions 1-10 and completing activities, How would you characterize the theory of Plate Tectonics influence on the earth’s surface. You might want to consider these questions while answering a. Is your earth a dynamic earth --- always changing ● Yes it is b. Will your earth look different in 10 million years and beyond? ● It will change significantly c. What is the ring of fire and why is plate tectonics regarded as the universal theory. ● The ring of fire represents the results of plate tectonics. The plates are not fixed but are constantly moving atop a layer of solid and molten rock called the mantle.

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d. Was Alfred Wegner onto something when he proposed his Continental Drift theory in the 1920’s ● People refer the continental drift as the taylor-wegener theory. Wegener foun that identical fossils could be foun on different continents, supporting his theory that continents which are now far apart were once linked. 12. The current scientific research regarding plate tectonics is “how do the plates” move --- the causes. a. Relationship Questions: 1. The term “convection” is used to describe the movement of plates. What is convection? Explain how convection works. ● COnvection currents describe the rising, spread, and sinking of gas, liquid, or molten material caused by the application of heat. 2. Thinking back to the interior parts of the earth (core, mantle, lithosphere), how is convection used to explain movement of continents. In your answer, use the general model of plate tectonics and explain the importance of the asthenosphere and convection results in “slab pull” ● Tectonic plates break apart and diverge where the mantle beneath is upwelling, Mid-ocean ridges develop (Ridge push), and the new lithosphere and crust form to replace the material that is moving away. Where plates converge, usually where the mantle is downwelling, one plate if forced beneath another. If the collision involves plates with he oceanic crust, subduction zones form where one plate descends into the mantle beneath the other plate (slab pull). Above these subduction zone chain of volcanoes and island arcs like the Aleutians, develop. 3. How does the lava-lamp theory explain what really is happening in the mantle when using convection processes? ● The earth’s manly has convection currents because of the heat of the core acts similarly to the light bulb in our lava lamp. The core’s heat energy is transferred to the mantle, causing it to rise toward the earth’s surface. Which is cooler. 4. Draw a diagram illustrating how convection and the lava-lamp theory move continental material. Possible Essay Questions: 1. What is the defining evidence that separates Wegner’s continental drift hypothesis from the theory of plate tectonics. ● The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, wegener published a paper explaining his theory that the continental landmasses were “drifting” across the earth, sometimes plowing through the oceans and into each other. 2. Explain the mechanics between the O-C, O-O and C-C convergent boundaries ● When plates converge, they do so in one of three settings: oceanic plates collide with each other O-O, Oceanic plates collide with continental plates O-C, or continental plates collide with each other forming C-C. 3. How is convection used to describe the movement of continents? a. Convection currents drive the movement of Earth’s rigid tectonic plates in the planet’s fluid molten mantle. In places where convection currents rise up towards the crust’s surface, tectonic plates move away from each other in a process known as seafloor spreading.

Earthquakes - Activity Sheet 100 points As always, I t’s all about relationships. As you prepare for exam-2, review the content below and formulate relationships between seismic waves, measuring earthquakes, interior parts of the earth and predicting earthquakes.. In many cases, don’t memorize, but explain in your own words and develop a picture in your mind regarding earthquake concepts. Most importantly, as you learn the concept and relationship, be able to explain the concept using the proper terminology. Please make sure you take a look at the probable exam essay questions at the end of this activity sheet. It’s recommended that you view the earthquake lecture in its entirety before answering questions. 1. What is an earthquake (scientifically speaking) a. Relationship questions 1. From lecture, how is throwing a rock in a calm pool of water related to earthquake rupture on the surface of the earth? ● It is similar because the surface of the pound is smooth and calm, but when you throw a rock it causes ripples across the water's surface. 2. If you were a frog sitting on a lily pad, what motions would you feel as the wave (disturbance) from the rock hitting the pond passes along the water surface. How would this relate to an earthquake on land. ● waves would make the lilypad go up and down just like an earthquake disturbs the surface and causes us to feel like we are going up and down 3. In your own words and after viewing the lecture, write a “scientific” definition of an earthquake. ● A scientific definition of an earthquake is defined as a formation of seismic waves, hypocenter, epicenter, all created from the focus inside the earth's crust. 2. Draw a block diagram and define the following common terms that apply to earthquakes a. Epicenter- rupture point directly above the focus b. b. Focus - The actual rupture that takes place c. c. Seismic Waves - Vibration released from an actual rupture point d. d. Hypocenter - the point within the earth where an earthquake rupture starts a. Relationship questions: 1. How is the epicenter related but different from the focus? ● The epicenter is on the surface and the focus is deep in the earth 2. How is the focus and hypocenter related? ● Focus and the hypocenter is basically the same thing and are synonymous with one another. 3. Why are seismic waves considered vibrations ● Seismic waves are considered vibrations because they are the result of the energy that is released, and this energy that is released is in the form of vibrations. 3. Earthquakes are measured using the seismograph. a. Relationship questions: 1. What does the seismograph measure during an earthquake? ● It measures the vibrations of the seismic wave that are released during an earthquake 2. Describe the differences between a seismograph and seismogram ● A seismogram is a piece of paper with lines that bounce up and down that record the movements of the earthquakes. A seismograph produces a measuring device.

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3. Why is it important to have several seismograph stations measuring the same earthquake? ● The reason is multiple stations are used in the process of triangulation. Triangulation allows scientists to pinpoint the epicenter. 4. The Elastic Rebound Theory: a. Relationship questions: 1. From lecture, describe in your own words, the elastic rebound theory ● The elastic bound theory explains how energy is released during an earthquake. As the earth’s crust deforms, the rocks which span the opposing sides of a fault are subjected to shear stress. 2. Now, from question 1 above, redescribe the elastic rebound theory using the terms: stress, strain, potential energy, kinetic energy, and vibrations. How did these terms fit into your first description of the elastic rebound theory ● Similar to an overstretched rubber band, prior to an earthquake, plates will move slowly causing stresses to build which will strain the earth's crust. As the stresses, or pressures, continue to build, there is a build-up and storing of potential energy. The rock is getting close to its " elastic limit ", the point at which it can no longer endure any more stress. Once this limit is reached , the rock will snap and release kinetic energy in the form of seismic waves. These seismic waves are vibrations that will shake the earth 3. How do aftershocks from an earthquake relate to the elastic rebound theory? ● After the snap of the plates the kinetic energy in the form of seismic waves, the rocks will attempt to move themselves back into their original position. The movement is what produces the aftershocks felt in an earthquake. 4. On your own, use a wooden pencil (a pencil that you are willing to destroy) and slowly bend the pencil until it breaks. a. As the pencil slowly bends (not breaking yet), how does this relate to rocks and the elastic rebound theory? ● Pressure begins to build in the potential energy stored b. Continue to bend the pencil and now it snaps. How does this relate to rocks and the elastic rebound theory? ● The rock snaps releasing stored energy in the form of seismic waves. c. Now, slowly bring the broken parts of the pencil back together. How does this relate to the elastic rebound theory and aftershocks? ● Rocks begin to reposition back into place, producing aftershocks 5. Good Vibrations (P, S and surface waves) a. Relationship questions: 1. After viewing the lecture, draw your best interpretations of P-wave (compression wave), S-wave (shear wave) and both the L and R surface waves. Make sure you view the wave animations in the lecture.

2. List the wave (vibrations) characteristics --- velocity and motion of waves ● P wave - compressional/longitudinal motion beneath the earth's surface, fastest seismic wave ( 6 km / s ) , travels through solids and liquids ● S wave - shearing motion beneath the earth's surface, travels at about 3.5 km/s, only travels through solids ● L wave - horizontal shearing, slower than P and S, travels on the surface ● R wave - similar to an ocean wave because it has an up and down motion, slowest wave 3. How are the body waves (P and S-waves) different when traveling through liquid and solid materials? Explain? ● P wave is the fastest can move through both liquid and solid. S wave only travels through solids. 4. If all the waves (P,S and surface waves) were lined up prior to the release of energy (earthquake), which waves would “shoot” out first, second and third ● The first wave to shoot out is the P-wave because it is the fastest. The next wave to shoot is the S-wave because it is faster than L and R waves. After the S wave, the L wave would reach next because it is faster than the R wave. The R wave would shoot out last because it is the slowest wave. 5. During an earthquake, do we feel the effects of all the waves? Which waves would one feel first, second and third? Explain? ● Yes, we do feel the efforts of waves. We would feel waves first, then the S waves second and the L waves third. 6. All waves are typically recorded onto a seismogram during an earthquake ---- Given what you learned about seismic waves, which wave would contact the seismograph first, second and third? ● The seismograph would be hit by the P wave, the S wave, then the L wave 7. Draw your own seismogram (you can access many depictions of seismograms from the internet) and see if you can pick out the P-wave arrival, S-wave arrival and the arrivals of surface waves.

● 6. Measuring earthquakes (The Richter, Mercalli and Moment Magnitude scales)-- You may need to watch this section of the lecture video several times over --- just saying. a. Relationship questions: 1. In your own words, describe the characteristics of each earthquake measuring scale: a. Richter Scale - Measures the ONLY amount of shaking that occurs in an earthquake using the seismograph. This amount of shaking is based on the logarithmic scale. b. Mercalli Scale- Measures the amount of damage done by an earthquake. Different areas that experienced the earthquake will be assigned a Roman Numeral that corresponds to the amount of damage in that area c. Moment Magnitude Scale - Measurement of work that is being done, it calculates the energy that is unleashed by the earthquake 2. Why is the Mercalli scale “scientifically” inaccurate?, thus allowing the onset of the Richter scale? ● It is based on people and their observation/opinions 3. The Richter scale measures the intensity (AMOUNT of SHAKING) using the seismograph a. What type of mathematical scale is used in the Richeter scale, Explain ● Base - 10 logarithmic scale meaning that in each order of magnitude is 10 time more intensive than the last one. A two 10 times more intense than a one and three is 100 times greater. b. For every Richter magnitude (M1, M2, M3…..M8) intensity increases by 10. Explain how intensity increases from one magnitude to the next. In other words, how much shaking takes place from one magnitude to the next.? ● From a M1 to an M2, there is a 1-step difference. This means that the amplitude of an M2 is 10 times larger than the amplitude of an M1. From an M1 to an M3, there is a 2-step difference. This means the amplitude of an M2 is 100 times larger than the amplitude of an M1. c. How much stronger in terms of intensity is an M8 magnitude compared to a M1 magnitude? ● The amplitude of M8 is 10 million time larger than the amplitude of an M1 d. Intensity increases by 10 (logarithmic scale) while the amount of energy release is 32 times more for every increase in Richter magnitude 1. How much more energy is released between a M1 and M3 magnitude earthquake? 1,024 2. How much more energy is released between a M1 and M5 earthquake? 10,000 times more energy 3. And finally, compare the energy release between a M1 and M8 earthquake? WOW!-- you should be saying that after you calculate the difference. 10000000 time bigger

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e. How is the Richter scale of measuring an earthquake different from the Mercalli scale? ● While the mercali scale describes the intensity of an earthquake based on its observed effects, the richter scale describes the earthquake’s magnitude by measuring the seismic waves that cause the earthquake. 4. How is moment magnitude scale the same as the Richter scale? ● They use the same values that are defined by the Richter scale, which means that they both use magnitudes from 1 to 10 5. What makes the Moment Magnitude scale more accurate than the Richter scale? ● Moment magnitude considers the rock properties of the rocks that have seismic waves traveling through them. This is important because not all rocks are the same, and seismic waves travel differently depending on the material 6. Why is the Moment Magnitude scale used today and basically replaces the Richter scale. ● The Richter scale does not provide accurate estimates for large-magnitude earthquakes. The moment magnitude scale is preferred because it works over a wider range of earthquake sizes and is applica 7. NOW, go back to question 6-1 of this section, and reanswer how you would describe each earthquake measuring scale ----- Use what you have learned. ● Richter Scale - a numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations ● Mercalli Scale - a twelve - point scale for expressing the local intensity of an earthquake 7. ACTIVITY: Fill a wide glass with water. If you have a small laser pointer, shoot a laser beam through the glass of water and observe how the beam exits the other side of the glass. You can use a flashlight beam, however the beam must be smaller than the glass. OR if you have a pool, shine the flashlight beam onto the surface of the pool water and observe where the beam hits the bottom of the pool. Now, answer the following questions. a. Relationship questions: 1. Describe what happens to the laser or flashlight beam as it enters the water and comes out the other side or hits the bottom the pool (if you are using a flashlight on the pool surface) ● The light beam bends and comes out from a different angle than it went in 2. Does the beam refract, get absorbed or reflect? Explain each term and describe and use the proper term that describes your answer in #1 above. ● It is refracted. Refracted waves bend as they pass from one object to another. Absorbed waves are completely blocked or stopped. Reflect waves are bounced back from a surface. 3. During the release of body wave vibrations (seismic waves) when an earthquake takes place, the body waves enter the earth’s interior layers ----- 1. Define what is meant by a seismic discontinuity? ● It describes a type of boundary within the earth’s interior that causes seismic waves to abruptly change in their velocities and direction 2. How is reflection, absorption and refraction related to seismic discontinuity? ● Refracted waves bend as they pass from one object to another. Absorbed waves are completely blocked or stopped. Reflect waves are bounced back from a surface. 3. How does a seismic discontinuity relate to the glass filled water activity you completed ● The seismic discontinuity of the water changed the way the Lazar beam 4. Looking at the ppt slide where it shows the graphical relationship of how P and S waves travel through the interior parts of the earth answer the following questions;

a. Describe what happens to both the P and S wave velocities as they come in contact with various earth interior layers. ● The speed of the P-Wave and S-waves increases as they travel through the mantle. b. At what depths, within the earth’s interior, are major seismic discontinuities? ● 2900 Km in depths c. What happens to the S-wave as it enters the outer core? Explain. ● It becomes absorbed because the S-waves cannot pass through liquids. d. Why do both the P and S waves slow down just below the lithosphere? ● the lower rigidity and compressibility of the rocks in the layer below the lithosphere. The zone below the lithosphere where seismic waves travel more slowly is called the low-velocity zone. e. How does your answer in “d” relate to the mechanics of Plate Tectonics? ● The ocean floors are continually moving, spreading from the center, sinking at the edges, and being regenerated. Convection currents beneath the plates move the crustal plates in different directions. 4. What is the shadow zone? a. How is the shadow zone (40 degree arc of no P or S waves) determined? ● The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent by the liquid core. b. What does the shadow zone tell scientists about the earth’s interior? ● The outer core is made of liquid c. If an M8 magnitude occurs along the SAF, where would the shadow zone be located on Earth? (You will need to research this one) New York 8. Can earthquakes currently be predicted??? Explain Why or Why not ● No, because scientists have to predict a small range of uncertainty as to the location and timing. 9. Most seismologists incorporate the seismic gap method for earthquake prediction. a. Relationship questions: 1. How is the term “probability” used to describe the seismic gap method or EQ prediction? ● Probability is describe the chances of an earthquake occurring in a particular area based on the frequency of the earthquakes that have already occured. 2. Draw a picture of California and the location of the SAF. Research EQ locations for the last 50-100years and create a pattern of EQ activity on your map. 1. Where is there a “gap” of EQ activity along the SAF ● The Carrizo plain area 2. How does this gap relate to the concept of predicting an EQ in this area ● seismic gap is a zone along a tectonically active area where no earthquakes have occurred recently , but it is known that elastic strain is building in the rocks . If a seismic gap can be identified , then it might be an area expected to have a large earthquake in the near future . 3. Based on the seismic gap studies of the SAF, explain why there is a 90% chance of a major EQ in our area M8 or above. ● There has not been a major earthquake along the SAF in a while.

10. Based on what you have learned in this EQ lecture and activity sheet, How would you craft an educated answer to someone if they asked you, “When and where is the big one (referring to an EQ) in California, what would a Bakersfield seismogram look like and what would we feel in terms of released vibrations? ● The big one would most likely occur in the carnival plane area. Bakersfield seismograph would give a massive magnitude and Bakersfield would feel massive vibrations. Possible Essay Questions for Exam-2 1. Contrast the difference between the Richter Magnitude and the Moment Magnitude Scales ● Richter magnitude scale, also called the Richter scale is used to measure the strength of the earthquake. But the limitations like location and frequency created the need for a more effective scale . The moment is a physical quantity that measures the total energy released in the earthquake. When the moment that we get from the seismograph, is then converted to a numerical value called moment magnitude. 2. Describe the characteristics of seismic waves released from a major earthquake and how these seismic waves propagate through the earth’s interior allowing scientists to understand the makeup of the earth’s interior. ● Seismic waves are those vibrations that carry the energy from the point of shaking. The study of these waves is called seismology. One way to learn about the interior of the earth is by observing the earthquake waves. These waves will be traveling in all directions from the area where the ground break. Primary and secondary waves are used to learn more about the Earth's interior.

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