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25 Cards in this Set
- Front
- Back
What was Alfred Wegner's hypothesis about the continents?
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Wegner's hypothesis was that all the continents were once joined together in a single landmass and have since drifted apart. |
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What are mid-ocean ridges?
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Mid-ocean ridges form when long-chains of mountains that rise up from the ocean floor.
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What is sea-floor spreading?
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Sea-floor spreading adds more crust to the ocean floor. At the same time, older strips of rock move outward from either side of the ridge
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What happens at deep-ocean trenches?
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In a process of tens of millions of years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.
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What is the theory of plate tectonics?
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The theory of plate tectonics states that Earth's plates are in slow, constant motion driven by convection currents in the mantle.
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How does stress change earth's crust?
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Tension, compression, and shearing work over millions of years to change the shape and volume of rock. |
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How do faults form?
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When enough stress builds up in rock, the rock breaks creating a fault.
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How does plate movements create new landforms?
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Over millions of years, the forces of plate movement can change a flat plain into features such as anticlines and synclines, folded mountains, fault-block mountains, and plateaus.
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What are seismic waves?
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Seismic waves are vibrations similar to sound waves. They travel through Earth carrying energy released by an earthquake?
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How are earthquakes measured?
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The amount of an earthquake's damages or shaking that is felt is rated using the Modified Mercalli scale. The magnitude or scale of an earthquake is measured on a seismograph using the Ricter scale or moment magnitude scale.
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How is an epicenter located? |
Geologists use seismic wave to locate an earthquake's epicenter.
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How did Wegner's hypothesis turn into the theory of plate tectonics?
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Scientists looked at his hypothesis and given time and new understandings(fossils and plants of plate movement. It turned into the theory of plate tectonics.
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What is the relationship between mid-ocean ridges, sea-floor spreading, and deep ocean trenches?
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New crust forms at mid-ocean ridges during the process of sea-floor spreading. During sea-floor spreading, the crusts spreads down and through the deep ocean trenches, the crust is subducted.
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What is the relationship between the stresses in Earth's crust and the formation of faults?
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The three stresses(tension, compression, and shearing) are stresses that break rocks which are known as faults.
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How does stress and movement along faults create new landforms?
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Tension pulls the rock apart. Compression smashes rock together. Shearing grinds rock between plates.
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What causes the movement and destruction we see and feel in an earthquake?
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The release of energy through the movement of tectonic plates.
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What is subduction, how does it work, why does it happen?
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Subduction is the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle again. As subduction occurs, crust closer to a mid-ocean ridge moves away from the ridge and toward a deep-ocean trench. Subduction occurs because the oceanic crust is cooler and denser than the continental crust which is hotter and less dense.
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Why is the continental crust less dense than the oceanic crust?
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The continental crust contains granite which is less dense than the oceanic crust which contains basalt.
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Why does the old crust subduct?
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It cools and becomes more dense as it cools.
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What is the relationship between subduction and earth's oceans?
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Sea-floor spreading can change the size and shape of oceans.The size of the oceans are determined by how fast new crust is being created at mid-ocean ridges and how fast old crust is being swallowed up at deep-ocean trenches.Oceans surrounded by trenches may shrink. Oceans with few trenches will probably grow larger.
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What are the three types of stress?
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Tension Stress, Compression Stress and Shearing Stress
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What are the three types of fault lines?
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Strike/slip Fault, Normal Fault, and Reverse Fault
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What are the three types of fault boundaries?
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Divergent Boundary, Transform Boundary, Convergent Boundary
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What type of stress creates each fault?
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Tension creates a normal fault. Compression creates a reverse fault. Shearing creates an strike/slip fault.
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What happens in a each type of fault?
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In a normal fault,the hanging wall moves down and the foot wall moves up. In a reverse fault, the hanging wall moves up and the foot wall moves down. In a strike/slip fault, the tectonic plates strike and slip past each other.
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