Transcript World Geog Ch 1_lesson6 volcanic mts

Unit 1: Land & Water Forms
World Geography 3200/3202
Course Outcomes
 In this lesson you will:
 1.1.8 Explain what causes a volcano to erupt. (k)
 1.1.9 Describe the characteristics of an ash and-cinder
cone, a shield cone, and acomposite cone. (k)
 1.1.10 Conclude how the location of active volcanoes is
related to places where plates meet. (a)
Terminology
 Volcano: An opening in the Earth’s crust through
which magma, gases, and ash erupt.
 Magma: Molten or melted rock found below Earth’s
crust. When magma cools to a solid it forms igneous
rocks.
 Lava: magma that flows at the Earth’s surface.
 Ash : Small pieces of lava that are blasted into the air
during volcanic eruptions.
 Vent: The opening through which the volcanic
material flows.
Types of Volcanoes
 Ash & Cinder Cone
 Shield Cone
 Composite Cone
Ash & Cinder Cone
 The simplest type of volcano.
 Symmetrical shape, steep sides, large crater. A single
vent.
 Very explosive. Lava is thick and slow flowing, often
blocking the vent  Boom!
Shield Cone
 Shape is broad and flat.
 The volcano is built of lava, which nearly always flows
from the vent.
 Eruptions are milder / the least explosive.
Composite Cone
 Shape is similar to ash and cinder, except it is built of
layers of ash, cinder, and lava.
 A network of magma vents develop inside, forming
mini-volcanoes.
 Eruptions can be explosive, followed by periods of
quiet activity.
Volcanoes: Review
 Which type of volcano is most explosive? Ash &
Cinder
 Which type of volcano is least explosive? Shield
 Which type of volcano is explosive at times and slow
flowing lava at times? Composite
Volcanoes: Review
 Which type of volcano has the thickest lava? Ash &
Cinder
 Which type of volcano has the thinnest, most liquid
lava? Shield
 Which type of volcano often has side vents?
Composite
 Which type of volcano has the gentlest slope? Shield
Volcanoes: Review
 Which type of volcano is steepest? Ash & Cinder
 What term is given to the opening of a volcano?
Crater
 Liquid, fluid, melted rock below the earth's surface is
known as: Magma
 Liquid, fluid, melted rock that reaches the earth's
surface is known as: Lava