Plate Tectonics According to the theory of plate tectonics, the movement of Earth’s plates produces volcanoes, mountain ranges, earthquakes, and features of the ocean floor. According to the theory of plate tectonics, the movement of Earth’s plates produces volcanoes, mountain ranges, earthquakes, and features of the ocean floor. What are Earth’s plates and what are they made of? What are Earth’s plates and what are they made of? Earth’s plates are large pieces of the lithosphere made up of solid rock. They include oceanic and continental crust. Earth’s plates are large pieces of the lithosphere made up of solid rock. They include oceanic and continental crust. What was Wegener’s hypothesis about Pangaea? What was Wegener’s hypothesis about Pangaea? The continents collided and formed a great landmass called Pangaea millions of years ago The continents collided and formed a great landmass called Pangaea millions of years ago What do scientists think is the cause of plate motion? What do scientists think is the cause of plate motion? Movement of material in the upper mantle, which drags the overlying plates along. Movement of material in the upper mantle, which drags the overlying plates along.

Plate Tectonics Describe how new features of Earth’s surface result from the movement of Earth’s plates. Describe how new features of Earth’s surface result from the movement of Earth’s plates. When plates collide, trenches, volcanoes or mountain ranges form. When plates pull apart, mid-ocean ridges, rift valleys or new oceans form. When plates collide, trenches, volcanoes or mountain ranges form. When plates pull apart, mid-ocean ridges, rift valleys or new oceans form. Continental Drift, Pangaea and Plate Tectonics. Continental Drift, Pangaea and Plate Tectonics. Continental Drift, Pangaea and Plate Tectonics Continental Drift, Pangaea and Plate Tectonics Exploring Plate Tectonics Exploring Plate Tectonics Exploring Plate Tectonics Exploring Plate Tectonics

Earth’s Crust in Motion Stress in the crust Stress in the crust Earthquakes Earthquakes Stress Stress Types of Stress Types of Stress Shearing Shearing Tension Tension Compression Compression How does deformation change Earth’s surface? How does deformation change Earth’s surface? It causes it to bend, stretch, break, tilt, fold and slide It causes it to bend, stretch, break, tilt, fold and slide Which type of deformation tends to shorten part of the crust? Which type of deformation tends to shorten part of the crust? Which type of deformation tends to shorten part of the crust? Which type of deformation tends to shorten part of the crust? Compression is the type of deformation that may shorten part of the crust by pushing it together Compression is the type of deformation that may shorten part of the crust by pushing it together

Earth’s Crust in Motion Kinds of faults Kinds of faults Kinds of faults Kinds of faults Strike-Slip Fault Strike-Slip Fault Normal Fault Normal Fault Reverse Fault Reverse Fault Which half of the reverse fault in the picture on pg. 361 slid up and across…the hanging wall or the footwall? Explain. Which half of the reverse fault in the picture on pg. 361 slid up and across…the hanging wall or the footwall? Explain. The hanging wall slipped up and across. If the footwall had moved up, the fault would be called a normal fault. The hanging wall slipped up and across. If the footwall had moved up, the fault would be called a normal fault. What force of deformation produces each fault? What force of deformation produces each fault? Strike-slip – shearing, normal – tension, reverse – compression Strike-slip – shearing, normal – tension, reverse – compression

Earth’s Crust in Motion Friction along Faults Friction along Faults What is friction and why does it exist? What is friction and why does it exist? Friction is the force that opposes the motion of one surface as it moves across another surface. Friction exists because surfaces are not perfectly smooth. Friction is the force that opposes the motion of one surface as it moves across another surface. Friction exists because surfaces are not perfectly smooth. Relate friction to the strength of earthquakes. Relate friction to the strength of earthquakes. Mountain Building and Uplift Mountain Building and Uplift Mountain Building and Uplift Mountain Building and Uplift Describe how mountains are formed by faulting Describe how mountains are formed by faulting Describe how mountains are formed by folding Describe how mountains are formed by folding What kind of formations do anticlines and synclines form? What kind of formations do anticlines and synclines form? Other than mountains, what else is formed by uplift? Other than mountains, what else is formed by uplift?

Earth’s Crust in Motion Fault Lines, Stress, and Earthquakes Fault Lines, Stress, and Earthquakes Fault Lines, Stress, and Earthquakes Fault Lines, Stress, and Earthquakes What are the 3 main types of stress in rock? What are the 3 main types of stress in rock? Describe the movements that occur along each of the 3 types of faults. Describe the movements that occur along each of the 3 types of faults. How does Earth’s surface change as a result of movement along faults? How does Earth’s surface change as a result of movement along faults?

Earth’s Crust in Motion What are the 3 main types of stress in rock? What are the 3 main types of stress in rock? Shearing, tension and compression Shearing, tension and compression Describe the movements that occur along each of the 3 types of faults. Describe the movements that occur along each of the 3 types of faults. Strike-slip fault: the rocks on either side of the fault slip sideways past each other with little up-or-down motion. Normal fault: the hanging wall slips downward past the footwall. Reverse fault: the hanging wall slides up and over the footwall. Strike-slip fault: the rocks on either side of the fault slip sideways past each other with little up-or-down motion. Normal fault: the hanging wall slips downward past the footwall. Reverse fault: the hanging wall slides up and over the footwall. How does Earth’s surface change as a result of movement along faults? How does Earth’s surface change as a result of movement along faults? Movement along faults can create mountains and valleys. Movement along faults can create mountains and valleys.

Measuring Earthquakes Where does an earthquake begin? How does the energy reach the surface? Where does an earthquake begin? How does the energy reach the surface? Earthquakes always begin in the lithosphere within 100 km of Earth’s surface. The seismic waves carry the energy. Earthquakes always begin in the lithosphere within 100 km of Earth’s surface. The seismic waves carry the energy. Relate seismic waves and the focus. Where is the energy the greatest? Relate seismic waves and the focus. Where is the energy the greatest? Seismic waves carry the energy of an earthquake away from the focus, through Earth’s interior and across the surface. The energy of the seismic waves that reach the surface is greatest at the epicenter. Seismic waves carry the energy of an earthquake away from the focus, through Earth’s interior and across the surface. The energy of the seismic waves that reach the surface is greatest at the epicenter. Describe the 3 categories of seismic waves and how they relate to one another. Describe the 3 categories of seismic waves and how they relate to one another.

Measuring Earthquakes How do geologists detect seismic waves? How do geologists detect seismic waves? Describe the 3 ways of measuring earthquakes. Describe the 3 ways of measuring earthquakes. The Mercalli Scale The Mercalli Scale How would you rate the damage to the Folignocity hall (pg. 371) on the Mercalli scale? How would you rate the damage to the Folignocity hall (pg. 371) on the Mercalli scale? The Richter Scale The Richter Scale The Moment Magnitude Scale The Moment Magnitude Scale How do geologists locate the epicenter? How do geologists locate the epicenter?

Distinguishing between faults: Normal Fault Normal Fault Normal Fault Normal Fault Your hanging wall drops below your footwall Your hanging wall drops below your footwall Reverse Fault Reverse Fault Reverse Fault Reverse Fault Your hanging wall moves up above your footwall Your hanging wall moves up above your footwall Your footwall looks like a foot. Your footwall looks like a foot. When it states “the hanging wall is above the fault”, they mean, regardless of the type of fault, your hanging wall sits on your footwall When it states “the hanging wall is above the fault”, they mean, regardless of the type of fault, your hanging wall sits on your footwall Let’s take a look using 2 binders Let’s take a look using 2 binders Hanging wall Foot wall

Volcanic Activity Let’s explore a volcano Let’s explore a volcano An eruption occurs when gases trapped in magma rush through an opening at the Earth’s surface, carrying magma with them An eruption occurs when gases trapped in magma rush through an opening at the Earth’s surface, carrying magma with them Where does the magma come from? What causes it to rise? Where does the magma come from? What causes it to rise? How does heat affect the flow of magma? How does heat affect the flow of magma? Describe magma high in silica. Is the lava thick or thin? What types of rocks does it produce? Describe magma high in silica. Is the lava thick or thin? What types of rocks does it produce? Describe magma low in silica. Is the lava thick or thin? What types of rocks does it produce? Describe magma low in silica. Is the lava thick or thin? What types of rocks does it produce?

Volcanic Activity Volcanoes can erupt quietly or explosively, depending on the silica content of the magma Volcanoes can erupt quietly or explosively, depending on the silica content of the magma What causes a quiet eruption versus an explosive one? What causes a quiet eruption versus an explosive one? What types of lava are produced by quiet eruptions? What types of lava are produced by quiet eruptions? What is produced by an explosive eruption? See pg 379 for a picture. What is produced by an explosive eruption? See pg 379 for a picture. How would you relate hot springs and geysers to volcanic activity? How would you relate hot springs and geysers to volcanic activity? Volcano hazards include pyroclastic flows, avalanches of mud, damage from ash, lava flows, flooding and deadly gases. Volcano hazards include pyroclastic flows, avalanches of mud, damage from ash, lava flows, flooding and deadly gases.

Volcanic Activity The phases of a volcano

Volcanic Landforms Landforms formed by magma: Landforms formed by magma: Magma that hardens beneath the surface forms batholiths, dome mountains, dikes and sills, which are eventually exposed by erosion Magma that hardens beneath the surface forms batholiths, dome mountains, dikes and sills, which are eventually exposed by erosion This would be caused by magma that rises through the cracks in the upper crust, but fails to reach the surface This would be caused by magma that rises through the cracks in the upper crust, but fails to reach the surface Landforms formed by lava and ash: Landforms formed by lava and ash: Lava and other volcanic materials on the surface create shield volcanoes, cinder cones, composite volcanoes and plateaus Lava and other volcanic materials on the surface create shield volcanoes, cinder cones, composite volcanoes and plateaus Calderas are formed when a volcano has emptied it’s magma chamber. See pg. 390 for an example Calderas are formed when a volcano has emptied it’s magma chamber. See pg. 390 for an example

Volcanic Landforms What features form as a result of magma hardening beneath Earth’s surface? What features form as a result of magma hardening beneath Earth’s surface? Volcanic necks, dikes, sills, batholiths, dome mountains Volcanic necks, dikes, sills, batholiths, dome mountains Describe how a dome mountain can eventually form out of magma that hardened beneath Earth’s surface Describe how a dome mountain can eventually form out of magma that hardened beneath Earth’s surface Magma forces its way upward through cracks in the crust, but overlying rock layers keep the magma from reaching the surface. The magma forces the rock layers to bend upward into a dome shape. When the rock layers wear away, the dome is exposed. Magma forces its way upward through cracks in the crust, but overlying rock layers keep the magma from reaching the surface. The magma forces the rock layers to bend upward into a dome shape. When the rock layers wear away, the dome is exposed. Describe 5 landforms formed from lava and ash. Describe 5 landforms formed from lava and ash. Shield volcanoes, cinder cone volcanoes, composite volcanoes, lava plateaus and calderas Shield volcanoes, cinder cone volcanoes, composite volcanoes, lava plateaus and calderas Describe the process that creates a lava plateau Describe the process that creates a lava plateau Thin, runny lava flows out of several long, horizontal cracks and travels far in all directions before cooling and hardening. Over time, layers of lava build up, forming a plateau. Thin, runny lava flows out of several long, horizontal cracks and travels far in all directions before cooling and hardening. Over time, layers of lava build up, forming a plateau.