PPT-Chapter 5: Volcanoes 5.1 Volcanoes and Plate Tectonics

Volcanoes Volcano mountain that forms in Earths crust when molten material magma reaches the surface Remember magma is molten rock below ground lava is molten rock at the surface . Chapter 5. Rigid Earth to Plate Tectonics. Learning Objectives. Know the different types of volcanoes and their associated features. Understand the relationship of the volcanoes to plate tectonics. Know what geographic regions are at risk from volcanoes. Yellowstone Park is not only spectacular but also unique. It is the result of three volcanic eruptions, the likes of which have never been seen in all of recorded history. The first eruption occurred 2 million years, followed by two more eruptions 1 million years and 600,000 years ago. Below Yellowstone Park there is a hot spot that is generating basaltic magma. At the time of each of their three eruptions, the magma chamber began to produce large volumes of basaltic magma. Because of its low viscosity, the basaltic magma quickly rose to the bottom of the granitic continental crust. However, because the density of basaltic magma (density about 3) is slightly higher than that of granite (density about 2.9) it could not force its way through the granite to the surface. Instead, it began to pool beneath the granitic crust. The amount of heat trapped within the molten basaltic magma was enough to melt the minerals making up the overlaying and surrounding granite, forming a growing mass of granitic magma. Granitic magma is highly viscous and extremely gas-charged. Although it rose only very slowly, the granitic magma advanced upwards by melting even more of its own overlying granitic rock. At some point, radial fractures began to form around the rising mass of granitic magma. These fractures allowed steam eruptions to vent gas. Shortly after, with the overlying granitic rock severely weakened by the fractures, the highly gas-charged granitic magma erupted. The land to a distance of 200 miles in all directions was decimated. Pyroclastic flows, the most destructive eruptive features known, swept across the countryside. Ash fell across the country from the eruption site to the Atlantic Ocean. Ash polluted the world’s atmosphere, blocked the energy of the Sun, and plunged the Northern Hemisphere into a frozen wasteland for years. Can such an eruption occur in the Yellowstone region again? All the evidence suggests that the magma chamber below Yellowstone Park is current rising. According to the director of the Yellowstone Volcanic Observatory, it is not a question of whether or not another super-eruption CAN happen; it’s a question of WHEN it will happen!. Volcanism is mostly focused at plate margins. Pacific Ring of Fire. This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region is the area known as the “Pacific Ring of Fire”.. What You Will Learn. Describe the formation and movement of magma. . Explain the relationship between volcanoes and plate tectonics. . Summarize the methods scientists use to predict volcanic eruptions. . Volcanism is mostly focused at plate margins. Pacific Ring of Fire. This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region is the area known as the “Pacific Ring of Fire”.. 6. th. year Geography. Learning Outcome. Revise Core Book. Chapters 1 – 3. Plate Tectonics. Earthquakes. Volcanoes. Examine the exam questions on these topics. Theory of Plate Tectonics. Earths plates move. 9.1 – How & Where do Volcanoes Form?. One of the most dramatic activities associated with plate tectonics is the eruption of a volcano.. Volcano refers to both:. The . opening. in Earth’s crust through which molten rock, gases, and ash erupt.. What You Will Learn. Describe the formation and movement of magma. . Explain the relationship between volcanoes and plate tectonics. . Summarize the methods scientists use to predict volcanic eruptions. . Where are the major zones of volcanism?. What are the parts of a volcano?. How do volcanic landforms differ?. Copyright © McGraw-Hill Education. Volcanoes. Review. convergent. New. volcanism. hot spot. Romans believed in Vulcan, their god of fire.. They thought that Vulcan worked at a hot forge, striking sparks as he made swords and armor for the other gods.. Hawaiians told legends of the wanderings of Pele, their goddess of fire.. . . Cause. most volcanoes are formed when two of Earth’s plate collide. the collision drives one of the plates under another . the plate that is under the other one begins to melt-->this melted rock is known as magma. : Western US. Authors: Ruth Powers (UNAVCO Master Teaching-in-Residence); . Becca Walker and Shelley Olds (UNAVCO). Activity Outcomes. Learners should be able to…. Describe how the locations of earthquakes, volcanoes, and velocity vectors from GPS stations in the Western United States inform us about plate boundary zones. Structure of the Earth. What are the different layers of the Earth?. Structure of the Earth. Inner core. 6000. °C. Solid metal. Structure of the Earth. Outer core. 4500-6000. °C. Liquid metal. Structure of the Earth. Structure of the Earth. Key terms . Earth’s Structure- How the Earth is made up beyond what we see. . Plate Tectonics- Understanding how the Earth’s surface is divided up into sections. . Inner Core- The central part of the Earth; made of solid iron. .