2 Introduction to Volcanoes Forces of Nature- National Geographic Video
3 Latitude and Longitude Review Latitudes are imaginary lines to the north and south of the equator (x- axis)Longitudes are imaginary lines to the east and west of the Prime Meridian (y-axis)Example: Plot the following Points(1, 4), (2, 3), and (5, 2)
6 Earthquake Locations Where did most of the Volcanoes occur? How is this similar to where earthquakes occur?How does plate tectonic movement effect the location of volcanoes?
7 Ring of FireThe volcanoes belt that circles the Pacific Ocean is called the Ring of Fire
8 Volcanoes at Subduction Zones Volcanoes Form at Subduction Zones VideoAt CONVERGENT BOUNDARIES the denser plate subducts below the less dense plate to form a trench. As this dense plate gets pulled into the mantle, it begins to meltThis melted rock rises toward the crust and forms a volcano
9 How do Volcanoes form in the middle of a plate? Volcanoes that do not form on plate boundaries form over Hot SpotsHot Spots VideoHot magma from the core rises through the mantle and heats the earth’s crust until it breaks through the crust.As it breaks through the crust, lava is spewed into the ocean and hardens into an island.The oceanic crust moves like a conveyer belt and forms a string of islands like the Hawaiian islands.
10 Anatomy of a VolcanoCan we go inside a volcano and see what it looks like?How could we learn what the inside of a volcano is like?
11 What does the inside of a volcano look like? In your notes, draw and label a picture of what you think the inside of a volcano looks like.
12 Anatomy of a Volcano Vocabulary Magma- Molten rock beneath the surfaceLava- Molten rock on the surfaceMagma Chamber- as magma rises to the surface, it forms a large pocket beneath the surface that holds the magmaPipe: a narrow crack in the crust through which magma flowsVent- central opening that allows the flow of magma to the surface (where magma leaves the pipe)Crater- the bowl-like depression over the vent at the summit of the cone
14 Cinder Cone Volcano A small, steep- sided volcano Made mostly of cinders with lava flow intermixedEruptions are small and often do not cause damage
15 Shield Volcano Usually wider than it is tall Made entirely of lava Near oceans or on oceanic crustEruptions are quiet, but lava causes significant damage
16 Composite Volcano A large, steep-sided volcano Made of alternating layers of lava flow and pyroclastic debrisPyroclastic Debris: ash, lava and hot volcanic gasErupt explosively or quietly
17 Life Cycle of Volcanoes Active Volcanoes: a volcano that is erupting now, has erupted in the recent past, and shows signs of erupting in the near futureDormant Volcano: a volcano that has not erupted recently, but has during recorded history. It is expected to erupt again in the future.Extinct Volcano: has not erupted in recorded history and will not likely erupt again.