Warm-up

What is your favorite holiday tradition?

Volcanoes

What are volcanoes?

A volcano is an opening in Earth that erupts gases, ash, and lava.

How do volcanoes form?Magma is less dense than the rock

around it, so it is forced toward the surface

Vent: Opening that magma flows through

Crater: The steep-walled depression around a volcano’s vent

Where do volcanoes occur?Divergent Plate Boundaries

– Plates move apart as magma comes up forming a volcano

Convergent Plate Boundaries– Oceanic Plates subduct under

Continental Plates and melt into magma that will sometime rise to form a volcano

Where do volcanoes occur?

Where do volcanoes occur?Hot Spots

– Areas between Earth’s mantle and core that are unusually hot.

Example:– Hawaiian Islands

Pacific Plate moving over a stationary hot spot.

Hot Spot Occurrence

What controls eruptions?

The more trapped gases, silica and water vapor the more explosive the eruption.

What controls eruptions?– quiet eruption -> Basaltic Magma, silica

poor

– Silica Rich: explosive eruption Granitic Magma, Mount St. Helens,

WA– Intermediate Silica: Quiet / explosive

eruption. Andesitic Magma, Convergent Plate

Boundaries, Krakatau, South America

Forms of VolcanoesShield Volcano

– Quiet eruptions– Silica poor – Basaltic lava– Layers buildup

and form a broad volcano with gently sloping sides

– Example: Hawaiian Islands

Forms of VolcanoesCinder Cone

Volcanoes– Explosive

eruptions – Silica rich – Granitic lava – Steep sides of

loosely packed tephra (ash)

– Paricutín, Mexico

Forms of VolcanoesComposite Volcano/

Stratovolcano– Varying

explosions depend on amount of silica and trapped gases.

– Andesitic lava – Dome shaped – Mount Saint

Helens, WA

Violent Eruptions1883: Krakatau,

Indonesia

1906: Vesuvius, Italy

1983: Kilauea, Hawaii

2000: Popocatepetl, Mexico

Terms you will need to know

Pyroclastic Flow- Ground hugging avalanche of tephra and gases

Lahar- Mudflow with rock fragmentsCaldera- A crater like depression left from a

prior eruptionSuperVolcano- a volcano created from a hot

spot that has the power to cause substantial damage

Volcano Carousel

Read your articleFill in graphic

OrganizerCreate a poster of

your volcano to present to the class

Warm-Up

The volcano handout you picked up!

https://www.youtube.com/watch?v=JRV4xTT8FB8

Pompeii RAFT

Role: Pompeii villager

Audience: yourself Form: Journal entry Topic: Pompeii

eruption

Be sure to include at least 5 volcanic facts in your Narration • Type of volcano • Type of lava flow • Type of Emissions • Type of Eruption • How the volcano formed

Study Guide

Work with a partner to complete your study guide

You have until 1:40