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Day 3. Let’s Review. Plate Boundaries Divergent Boundary – moving apart - Form volcanoes and new crust Convergent Boundary – moving together - Form mountains, trenches, and volcanoes Sliding Boundary – moving sideways past each other - Form earthquakes .
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Let’s Review Plate Boundaries • Divergent Boundary – moving apart - Form volcanoes and new crust • Convergent Boundary – moving together - Form mountains, trenches, and volcanoes • Sliding Boundary – moving sideways past each other - Form earthquakes
We know that most major changes to Earth’s surface happen at or near plate boundaries. • At these boundaries there are faults, which are cracks in Earth’s crust where movement takes place. • The movement of rocks along a fault is called faulting. • Along a fault, rocks often bend, fold, and break. The plates jolt into new positions, which cause the earth to shake. As the earth shakes, it sends out waves of energy known as seismic waves. • These waves cause EARTHQUAKES.
An earthquake is a violent shaking of Earth’s crust and is caused by the release of built-up energy along a fault. • The energy released depends on how much rock breaks and how far the blocks of rock move. National Geographic Earthquakes 101 Track the most recent earthquake
Tsunami • A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet, onto land. • These huge waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. • When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami. • Tsunamis may also be caused by underwater landslides or volcanic eruptions.
Volcano • A volcano is an opening in Earths surface through which melted rock, hot gases, and ash burst forth, or erupt.
Ring of Fire Many earthquakes and volcanoes occur in an area that borders the Pacific Ocean. This area has been named the Ring of Fire. The Ring of Fire has 452 volcanoes and is home to over 50% of the world's active and dormant volcanoes. Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.
Notes • Faulting causes EARTHQUAKES. • AN EARTHQUAKE is a violent SHAKING of Earth's crust and is caused by the RELEASE of built-up energy along a FAULT. • A TSUNAMI is a series of ocean WAVES that sends surges of WATER onto land. • A VOLCANO is an opening in Earth’s SURFACE through which melted ROCK, hot gases, and ASH erupt. • Ring of Fire: Area that borders the PACIFIC Ocean. It is home to 50% of the world's volcanoes and 81 % of earthquakes.
How Do Volcanoes Form? • A volcano is formed by pressure building up below the Earth’s crust. Magma forces its way through weaknesses in the earth's crust. When the magma emerges it is called lava. When it cools, it solidifies into rock. • The shape of the volcano depends on the type of lava.
How Do Mountains Form? • Mountains are formed a few different ways. • Most mountains form at plate boundaries. • Even though mountains seem like they will be here forever, they are always being formed and destroyed.
Fold Mountains • Most of the largest mountain ranges form where two plates crash into each other and force layers of rock into folds. Andes Mountains
Let’s See For Ourselves… • Paper clip your paper strip to your folder. • Place one hand on each end of the paper. • Gently simulate the plate movement at a convergent boundary. • What happened? • This is how folded mountains form. • What do you think will happen if the rock is more rigid or has more applied pressure?
Fault-Block Mountains • Form where faulting happens - (Where rocks break into blocks!) • These blocks may move in several ways along one or more faults to form mountains. • Faulting may form high cliffs when a large piece of rock is forced upward or downward.
Straw • Place the middle of your straw under your paper clip. • Place one hand on each end of the straw. • Simulate the plate movement at a convergent boundary by pushing the two ends together. • What happened?
Mountain Formation Brainpop Complete Handout- Due Tomorrow!