Day 30: Volcanism

Objective: Warm-Up

You will use the theory of plate tectonics to explain the changes that occur in the earth’s surface. (Volcanism)

KWL Chart about volcanoes (3 for each column) I will call on 9 people to fill in the chart on the IWB so be ready!

Day 30: Volcanism

Objective: Warm-Up

You will use the theory of plate tectonics to explain the changes that occur in the earth’s surface. (Volcanism)

REVIEW PLATE

TECTONICS

Volcanoes 101After the video clip, you will be asked to SUMMARIZE the video clip. Be sure to include the main points.

(4 Sentences OR 8 Bullets)

Volcano Terminology (Volcanism)

Vulcan – Roman god of fire and metalworking. Lived under mount Etna . Mountains which spit fire were known as volcanoes.

 Volcano – Landform that develops on the surface of the earth where magma and gases erupt through a vent.

 Magma – molten rock. Intrusive (inside the earth)

 

Volcano Terminology (Volcanism)

Lava – molten rock. Extrusive (outside, on the surface)

 Volcanology – the study of volcanoes.

 Volcanologist – a scientist who studies volcanoes

How do Volcanoes Form?Volcanoes form two ways – Plate tectonics

and Hot spots.

Plate tectonics – convergent plate boundaries (colliding)

ocean / continental –volcanoocean / ocean – island arc

A. The ocean plate in both cases is subducted beneath the other plate.

B. The ocean plate is melted. Forms magma.C. The magma rises.D. The rising magma puts pressure on the

surface causing it to dome upward, forming a volcano.

E. The volcano erupts if the pressure continues. 

Plate tectonics – convergent plate boundaries (colliding)ocean / continental –volcanoocean / ocean – island arc

Subduction Zone

Hot SpotsAn area in the mantle where magma

is created and continuously rises to the surface.

It is believed that a hot spot is responsible for the creation of the Hawaiian Islands.

WHERE ARE VOLCANOES FOUND:

 Volcanoes are usually found near convergent plate boundaries.

 

Ring of fire – An area which encircles the Pacific Ocean where there is a great deal of volcanic activity.

Fissure – a crack in the Earth’s surface where lava flows out from. Similar to a volcano only the crust does not dome upward.

Ring of Fire- Pacific Plate

Think Back: What is

happening to the Pacific

plate? Why?

Fissure

ClosureWhat types of plate boundaries

result in the formation of volcanoes?

The Pacific plate is shrinking because it is being subducted on all sides. What is the boundary’s nickname?

You will use the composition, size and eruption type of volcanoes in order to classify volcanoesMatch the following terms: 1. Vulcan A. molten rock

intrusively2. Volcanologist B. molten rock

extrusively3. Volcanology C. Roman god of fire4. Lava D. Person who studies

volcanoes5. Magma E. The study of

volcanoes

Objective

Types of Volcanoes

ViscosityThe resistance to flow. Substances which do not flow easily have a high viscosity. (HONEY or MOLASSAS) Substances which flow easily have a low viscosity.

Types of Eruptions: Violent Eruptions-Explosive Quiet Eruptions

Silica- high viscosity-violent eruption

Water- low viscosity- quiet eruption

Volcanic Activity: ActiveVolcanoes which

have erupted during recent times.

Volcanic Activity: DormantVolcanoes that have not erupted in

recent times but show some signs of volcanic activity.

Volcanic Activity: ExtinctVolcanoes which

have not erupted during recorded history and do no seem capable of erupting.

VOLCANIC FEATURES

Pipe or Vent: Magma ChamberVertical tunnels

extending from the magma chamber to the surface of the earth.

The channel or pathway the lava flows during an eruption.

Area below the surface where magma collects

Plume Pyroclastic RockA large volcanic

dust cloud which occurs during a violent eruption.

Contains pyroclastic rock and gases.

Any rock formed when lava or solid rock erupts explosivelyTypes of

Pyroclastic Material: Fine ashCoarse ashCinders Volcanic bombs

Ash Flows Glowing clouda mixture of volcanic ash, gases, and

pyroclastic particles that flows rapidly along the earth’s surface at speeds up to 300 km/hr. EXTREMELY HOT!

CalderaA large circular hole that forms when part

of the volcano collapses into the magma chamber after an eruption

Closure1. How are cinder cone volcanoes formed?

What is its explosion type?

2. Provide some of the characteristics of a shield volcano? What is its explosion type?

3. Why does a composite volcano have alternating layers of ash and lava? What is its explosion type?